Transformation of cotton plants

ABSTRACT

A method for producing transformed cotton plants. The method comprising providing cotton explants, incubating the cotton explant in the presence of a vector comprising a selectable marker to produce treated explants, growing the treated explants to produce callus and selecting transformed callus.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of application Ser. No. 08/122,090 filed Sep. 14,1993, which is a division of application Ser. No. 07/680,048 filed Mar.29, 1991, now U.S. Pat. No. 5,244,802, which is a continuation ofapplication Ser. No. 07/122,200 filed Nov. 18, 1987, now abandoned.

FIELD OF THE INVENTION

This invention relates to the production of new strains of cotton.

BACKGROUND OF THE INVENTION

This invention is directed to plant regeneration and transformation ofcotton, particularly cotton of the species Gossypium hirsutum L.

In recent years many tissues of diverse origin from plants belonging todifferent taxonomic groups have been established as in vitro tissueculture. Some of the factors controlling growth and differentiation ofsuch cultures have also been determined. The establishment of subtleinteractions among the different groups of plant hormones, and plantgrowth regulators operating either directly or indirectly, alone or insynergistic combination, have given to some degree an insight intocertain interrelationships that may exist among cells, tissues andorgans. The information is however by no means complete.

For some time it has been known that plant cell cultures can bemaintained in a non-differentiating proliferative state indefinitely. Ithas, however, only been recently found that redifferentiation oftissues, organs or whole plant organisms can be experimentally induced.Since the demonstrations by Skoog et al. [“Chemical regulation of growthand organ formation in plant tissues cultured in vitrol” Symp. Soc. Exp.Biol. 11 18-130 (1958), incorporated herein by reference] that therelative ratio of a cytokinin to an auxin determines the nature oforganogenesis in tobacco pith tissue. Reorganization or regenerationfrom callus cultures includes the formation of shoot primordia orembryos, both of which ultimately lead to plantlet development in vitro.

The tendency for organogenesis vs. embryogenesis still depends upon thespecies involved and the presence of certain triggering factors whichare chemical and/or physical in nature.

In 1902, Haberlandt [“Kulturversuche mit isolierten pflanzenzellen,”Mat. K I. Kais. Akad. Wiss. Wien 111 62, incorporated herein byreference] postulated that plant cells possessed the ability to produceentire plants and predicted that this would someday be demonstrable incell cultures. In 1965, Reinert [“Untersuchungen uber die morphogenesean Gewebekulturen,” Ber. dt. Bot. Ges. 71 15] and Steward et al.[“Growth and organized development of cultured cells/II. Organization incultures grown from freely suspended cells,” Am. J. Bot. 45 705-708]working independently, confirmed the occurrence of in vitro somaticembryogenesis. (Both references are incorporated herein by reference.)In experimentally manipulating somatic embryogenesis it is believed thattwo components of the culture media, an auxin and the nitrogen source,play crucial roles.

It has also been shown that the process of somatic embryogenesis takesplace in two stages: first, the induction of cells with embryogeniccompetence in the presence of a high concentration of auxin; and second,the development of embryonic cell masses into embryos in the absence ofor at a low concentration of auxin.

The induction of organogenesis or embryogenesis leads to distinctstructural patterns in the callus. Detailed study of several plantspecies has enabled certain generalizations to be made about thedevelopmental pathways leading to shoot, bud or embryo development.

The application of tissue culture techniques to the regeneration ofplants via organogenesis or embryogenesis remains perhaps the mostimportant contribution of basic studies in morphogenesis to commercialapplication.

Beasley reported the formation of callus in ovule cultures of cotton in1971 [“In vitro culture of fertilized cotton ovules,” Bioscience 21906-907 (1971), incorporated herein by reference]. Later, Hsu et al.[“Callus induction by (2-chlorethyl) phosphoric (CPA) acid in culturedcotton ovules,” Physiol. Plant 36 150-153 (1976), incorporated herein byreference] observed a stimulation of growth of calli obtained fromovules due to the addition of CPA and gibberellic acid to the medium.Callus cultures from other explants such as (a) leaf [Davis et al. “Invitro culture of callus tissues and cell suspensions from okra (Hibiscusesculentus) and cotton (Gossypium hirsutum), “In vitro 9 395-398 (1974),both incorporated herein by reference] (b) hypocotyl [Schenk et al.“Medium and technique for induction and growth of monocotyledonous anddicotyledonous plant cell cultures,” Can. J. Bot. 50 199-204 (1972),incorporated herein by reference] and (c) cotyledons [Rani et al.“Establishment of Tissue Cultures of Cotton,” Plant Sci. Lett. 7 163-169(1976), incorporated herein by reference] have been established forGossypium hirsutum and G. arboreum.

Katterman et al. [“The influence of a strong reducing agent uponinitiation of callus from the germinating seedlings of Gossypiumbarbadense,” Physiol. Plant 40 98-101 (1977), incorporated herein byreference] observed that the compact callus from cotyledons of G.barbadense formed roots, and in one instance regeneration of a completeplant as also obtained. Smith et al. [“Defined conditions for theinitiation and growth of cotton callus in vitro, Gossypium arboreum,” Invitro 13 329-334 (1977), incorporated herein by reference] determinedconditions for initiation and subculture of hypocotyl-derived callus ofG. arboreum. Subsequently, Price et al. [“Callus cultures of six speciesof cotton (Gossypium L) on defined media,” Pl. Sci. Lett. 8 115-119(1977), and “Tissue culture of Gossypium species and its potential incotton genetics and crop improvement,” Beltwide Cotton ProductionResearch Conference Proc. pp. 51-55 (1977), of the National CottonCouncil, Memphis, each incorporated herein by reference] definedconditions for the initiation and subculture of callus from five speciesof Gossypium.

One of the common problems in establishing cultures of many plantspecies is the “browning” of the explant in the culture medium. Incotton, this leaching of polyphenols was overcome by replacing sucrosewith glucose, and by transferring the cultures to a fresh medium every10 days. After 3 or 4 passages on glucose supplemented medium, thebrowning completely disappeared and the cultures could be transferredback to sucrose-supplemented media. Although difficulties with theinduction, browning and maintenance of calli during subcultures havebeen overcome with certain Gossypium species, all attempts to regenerateplants from callus cultures have been either unsuccessful or haveinvolved several time-consuming steps. Davidonis et al. [“PlantRegeneration from Callus Tissue of Gossypium hirsutum,” L. Plant Sci.Lett. 32 89-93 (1983), incorporated herein by reference] reported theeventual formation of embryos two years after the initiation of culture.

Although many growth substances, such as natural phytohormones andsynthetic growth regulating compounds have been utilized in tissueculture media to bring about plant regeneration in vitro, nogeneralization, much less specifics, of the effects of differentsubstances on plant regeneration has been arrived at. Indeed, the samesubstances, when applied to different plant species, may either inhibitgrowth, enhance growth, or have no effect whatsoever. Therefore, asidefrom certain standard procedures, it remains necessarily a difficulttask to arrive at a working protocol for plant regeneration for any newspecies and by many orders of magnitude a more difficult task to achieveplant transformation.

The present invention provides a method for the rapid regeneration ofcotton plants from segments excised from seedlings. The method describedoffers a high degree of repeatability and reliability and it enablesgenetic transformation of cotton plants.

SUMMARY OF THE INVENTION

The present invention describes a method for producing transformedcotton plants. The method comprises providing cotton explants. Thecotton explant is incubated in the presence of a vector comprising aselectable marker to produce treated explants The treated explants aregrown to produce callus. The callus is selected for transformed callus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 presents diagrammatically preferred procedures for development ofcotton plants from seed by tissue culture techniques with a showing ofestablishing zones of transformation.

FIG. 2 is a photo illustration of embryogenic callus (10) of cotton withsomatic embryos (12) at various stages of development including leaf(14) and root (16).

FIG. 3 is a photo illustration of a somatic cotton embryo at a lateglobular stage isolated to form the embryogenic callus culture asdepicted in FIG. 2.

FIG. 4, as with reference to FIG. 2, is a photo illustration of embryosand young plantlets (18) of cotton developing on an embryo germinationmedium.

FIG. 5 is a photo illustration of small clumps of embryogenic cells fromsuspension cultures of cotton.

FIG. 6 is a photo illustration of a globular stage embryo from asuspension culture.

FIG. 7 illustrates germinating embryos obtained from suspension culturesshowing emerging leaves (14) and roots (16).

FIG. 8 illustrates the development of plantlets of cotton growing on theembryo germination medium.

FIGS. 9 to 15 depict the genetic transformation of cotton, with FIG. 9showing the development of cell colonies (20) from transformed cottoncells containing a gene for kanamycin resistance.

FIG. 10 shows somatic embryos developing from the selected antibioticresistance cells of FIG. 9 on an antibiotic-supplemented medium.

FIG. 11 exemplifies transformed somatic embryos established to havekanamycin resistance and transformed to have resistance to the herbicideglyphosate.

FIG. 12 exemplifies cotton plants obtained by inoculating tissues withAgrobacterium containing a mutant AroA gene and thereafter growing thetissues on a non-selective media.

FIG. 13 shows germinating somatic embryos of variety B1644 obtained fromsuspension cultures treated with the vector pCIB10/BTA-5, and selectedon kanamycin (50 mg/L) or G418 (25 mg/L) supplemented media.

FIG. 14 shows plantlets developed from the embryos of FIG. 13.

FIG. 15 shows a plantlet of the variety Siokra developed fromtransformed embryos exhibiting a resistance to kanamycin.

FIG. 16 shows the construction of mp19/bt, a plasmid containing the 5′end of the Bt protoxin gene.

FIG. 17 shows the construction of mp19/bt ca/del, a plasmid containingthe CaMV gene VI promotor fused to the 5′ end of Bt protoxin codingsequence.

FIG. 18 shows the construction of p702/bt, a plasmid having the 3′coding region of the protoxin fused to the CaMV transcriptiontermination signals.

FIG. 19 shows the construction of PBR322/bt 14, containing the completeprotoxin coding sequence flanked by CaMV promotor and terminatorsequences.

FIG. 20 shows the construction of pRK252/Tn903/BglII.

FIG. 21 shows the construction of pCIB5.

FIGS. 22 & 23 shows the construction of pCIB4.

FIG. 24 shows the construction of pCIB2.

FIG. 25 shows the construction of pCIB10, a broad host range plasmidcontaining T-DNA borders and gene for plant selection.

FIG. 26 shows the construction of pCIB10/19Sbt.

FIG. 27 shows the construction of pCIB710.

FIG. 28 shows the construction of pCIB10/710.

FIG. 29 shows the construction of pCIB10/35Sbt.

FIG. 30 shows the construction of pCIB10/35Sbt(KpnI).

FIG. 31 shows the construction of pCIB10/35Sbt(BclI).

FIG. 32 shows the construction of pCIB10/35Sbt(607)

FIG. 33 depicts the vector DEI PEP10.

FIG. 34 is a photo showing a field trial made up of cotton regenerantsplanted in a Verticillium infested field.

FIG. 35 is a photo showing progeny of a regenerated SJ4 plant in thefield trial shown in FIG. 33. A somaclonal variant with improvedtolerance to Verticillium fungus is indicated by the arrow.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to the regeneration by tissue cultureof cotton plants particularly plants of the genus Gossypium hirsutumfrom somatic cells for propagation in the field. Optionally, the cellsmay be transformed to include foreign genetic information.

The various growth medium useful in accordance with this invention areas follows:

Seed Germination Growth Medium Composition of Modified White's StockSolution [Phytomorphology 11 109-127 (1961) Incorporated Herein byReference]

Concentra- tion per Component 1000 ml. Comments MgSO₄.7H₂O 3.6 gDissolve and make up Na₂SO₄ 2.0 g the final volume to 1000 ml.NaH₂PO₄.H₂O 1.65 g Label White's A Stock. Use 100 ml/l of final medium.Ca(NO₃)₂.4H₂O 2.6 g Dissolve and make up KNO₃ 800 mg the final volume to1000 ml. KCl 650 mg Label White's B Stock. Use 100 ml/l of final medium.Na₂MoO₄.2H₂O 2.5 mg Dissolve and make up CoCl₂.6H₂O 2.5 mg the finalvolume to 100 ml. MnSO₄.H₂O 300 mg Label White's C Stock. ZnSO₄.7H₂O 50mg Use 1.0 ml/l of final medium. CuSO₄.5H₂O 2.5 mg H₃BO₃ 50 mg Fe EDTAUse 10 ml/l of MSFe EDTA. Organic Use 10 ml/l of MS organic.

Callus Growth/Maintenance Medium Composition of Murashige & Skoog (MS)Stock Solutions [Physiol. Plant 15 473-497 (1962) Incorporated Herein byReference]

Concentra- tion per 1000 ml. Component of Stock Comments NH₄NO₃ 41.26 gDissolve and make up KNO₃ 47.50 g the final volume to 1000 ml.CaCl₂.2H₂O 11.00 g Use 40 ml/l of final medium. MgSO₄.7H₂O 9.25 g KH₂PO₄4.25 g KI 83 mg Dissolve and make up H₃BO₃ 620 mg the final volume to1000 ml. MnSO₄.H₂O 1690 mg Label MS - Minor. ZnSO₄.7H₂O 860 mg Use 10ml/l of final medium. Na₂MoO₄.2H₂O 25 mg CuSO₄.5H₂O 2.5 mg CoCl₂.6H₂O2.5 mg Nicotinic acid 50 mg Dissolve and make up Pyridoxin HCl 50 mg thefinal volume to 1000 ml. Thiamine HCl 10 mg Label MS - Organic. Freezein 10 ml aliquots. Use 10 ml/l of final medium. Fe EDTA 2.78 g Dissolve2.78 g of FeSO₄.7H₂O Fe SO₄.7H₂O 3.73 g in about 200 ml of deionizedwater. Na₂ EDTA.2H₂O Dissolve 3.73 g of Na₂ EDTA.2H₂O (disodium salt ofethylenediaminetetraacetic acid dihydrate) in 200 ml of deionized waterin another beaker. Heat the Na₂ EDTA solution on a hot plate for about10 minutes. While constantly stirring, add FeSO₄ solution to Na₂ EDTAsolution. Cool the solution to room temperature and make up the volumeto 1000 ml. Label MS EDTA. Cover bottle with foil and store inrefrigerator. Use 10 ml/l of final medium. Thiamine HCl 50 mg Dissolveand make up the volume to 500 ml. Label MS - Thiamine. Use 4.0 ml/l offinal medium. As if required. Inositol 10 g Dissolve and make up Glycine0.2 g the final volume to 1000 ml. Label MS - glycine/inositol. Use 10ml/l of final medium.

Plant Germination Medium Composition of Beasley and Ting's StockSolutions [Am. J. Bot. 60 130-139 (1973) Incorporated Herein byReference]

Conc. per Component 1000 ml. Comments KH₂PO₄ 2.72 g Dissolve and make upH₃BO₃ 61.83 mg the volume to 100 ml. Na₂MoO₄.2H₂O 2.42 mg Label B&T - AStock. Use 10 ml/l of final medium. CaCl₂.2H₂O 4.41 g Dissolve and makeup KI 8.3 mg the volume to 100 ml. CoCl₂.6H₂O 0.24 mg Label B&T - BStock. Use 10 ml/l of final medium. MgSO₄.7H₂O 4.93 g Dissolve and makeup MnSO₄.H₂O 169.02 mg the volume to 100 ml. ZnSO₄.7H₂O 86.27 mg LabelB&T - C Stock. CuSO₄.5H₂O 0.25 mg Use 10 ml/l of final medium. KNO₃25.275 g Dissolve and make up the volume to 200 ml. Label B&T - D Stock.Use 40 ml/l of final medium. Nicotinic acid 4.92 mg Dissolve and make upPyridoxin HCl 8.22 mg the final volume to 100 ml. Thiamine HCl 13.49 mgLabel B&T - Organics. Use 10 ml/l of final medium. Fe EDTA Use 10 ml/lof MS Fe EDTA. Inositol 100 mg/l of final medium. NH₄NO₃ (15 μM) 1200.6mg/l of final medium.

With any of the above solutions, the following procedure is used toprepare one liter of the medium. There is provided as a base, 200 ml ofdeionized water and the various stock solutions are added in the amountsstated for 1 liter. For example, if there is to be employed 10 ml of astock in the final medium, then 10 ml of the stock are added to the 200ml of the distilled water. To ensure the salts stay in solution, stocksolutions are normally added in the order shown in the formulationsabove. After thoroughly mixing additional deionized water is added tothe mixture to bring it to, as required 500 ml, and the mixture adjustedin pH to a value of from about 5.8 to 6.0. The final volume is broughtto 1,000 ml and there is normally added tissue culture Agar, or itsequivalent to a level of about 0.8% by weight. This is to provide somesolidity to solution to reduce flow. The mixture is then autoclaved forabout 5 to 20 minutes at a pressure 15-21 lbs/in² to kill anycontaminating organism, and suitably labeled and stored as a sterilemedium.

Briefly, cotton seeds are sterilized and germinated on a suitable seedgermination medium such as a basal agar medium in the dark for a timesufficient to produce seedlings. The normal period of growth is up toabout 4 weeks, typically 7 to 14 days.

Segments of explants are excised from the seedling. It is preferred thatthe explant come from the hypocotyl or cotyledon. In the alternative,one can equally use immature embryos obtained from the developing fruitsof greenhouse or field grown cotton plants as the explant. The explantsegments are cultured on a suitable first callus growth medium,preferably a or full Murashige and Skoog (MS) nutrient medium containingglucose. Growth occurs by culturing at a temperature of from about 25 toabout 35° C. in a light/dark cycle of about 16 hours of light and above8 hours of dark. Culturing is the procedure whereby the medium isreplaced at periodic intervals as the nutrients are consumed andcontinued for approximately about 3 to about 4 weeks, or untilundifferentiated callus are formed. The callus are transferred to asecond callus growth medium, preferably an MS medium supplemented withnaphthaleneacetic acid (NAA) and sucrose as the carbon source andcultured for three to four months to produce embryos.

The embryos may then be maintained in the second callus growth medium tomaintain an embryo supply or transferred to a plant germination mediumsuch as Beasley and Ting's medium preferably containing caseinhydrolysate and source of ammonium cultured for 2 to 3 weeks to produceplantlets.

The plantlets are transferred to soil under high humidity conditions,then transplanted to larger pots in a greenhouse and finally transferredto the field for growth to maturity.

The methods briefly described herein have been successfully employed toinduce somatic embryo formation in cotton of the species Gossypiumhirsutum by tissue and suspension cultures and, ultimately, to obtainmature plants from hypocotyl and cotyledon derived callus cultures ofAcala varieties of Gossypium hirsutum including Acala SJ2, Acala SJ4,Acala SJ5, Acala SJ-C1, Acala B1644, Acala B1654-26, Acala B1654-43,Acala B3991, Acala GC356 (plants not obtained), Acala GC510, Acala GAM1,Acala Royale, Acala Maxxa (callus only formed), Acala Prema, Acala B638(plants not formed), Acala B1810, Acala B2724, Acala B4894, Acala B5002(plants not formed), non Acala “picker” Siokra, “stripper” varietyFC2017, Coker 315, STONEVILLE 506, STONEVILLE 825 (plants not formed),DP50 (callus only formed), DP61 (callus only formed), DP90 (callus onlyformed), DP77 (callus 6only formed), DES119 (callus only formed), McN235(callus only formed), HBX87 (plants not formed), HBX191 (callus onlyformed), HBX107 (callus only formed), FC 3027, CHEMBRED A1 (callus onlyformed), CHEMBRED A2 (callus only formed), CHEMBRED A3 (callus onlyformed), CHEMBRED A4 (callus only formed), CHEMBRED B1 (callus onlyformed), CHEMBRED B2, CHEMBRED B3 (callus only formed), CHEMBRED C1(callus only formed), CHEMBRED C2 (callus only formed), CHEMBRED C3(callus only formed), CHEMBRED C4, PAYMASTER 145 (callus only formed),HS26 (callus only formed), HS46 (callus only formed), SICALA (plants notformed), PIMA S6 (plants not formed) and ORO BLANCO PIMA (plants notformed). Cultures have been transformed to normal plants with noveltraits or properties.

The Acala SJ2 was obtained from a the cross AXTE1×NM 2302. The AcalaSJ4, SJ5, SJ-C1, B1644, B1654-26, B1654-43, B3991, GC356, GC510, GAM1were obtained from the cross C6TE×NM B3080. Acala Royale was obtainedfrom the cross [C6TE×NM B3080]×[AXTE 1-57×TEX E364]. Acala Maxxa wasobtained from the cross [S196×1900-1]×[12302-4×(C6TE×B7378)]. AcalaPrema was obtained from the cross [ATE-11×NM49-2]×[C6TE×NM B3080].

More particularly, the procedure involves first the sterilizing of thecotton seeds. Suitable sterilization may be achieved by immersing theseeds in 95% ethanol for 2 to 3 minutes, rinsing in sterile water one ormore times, then soaking the seeds in a 15% solution of sodiumhypochlorite for 15 to 20 minutes, and rinsing several times withsterile water.

The sterilized seeds are then transferred to a first medium, termed aseed germination medium. A seed germination medium is one of normal saltcontent. A suitable germination medium is a basal agar medium, includingWhite's medium or half-strength MS medium. (One-half ingredientstrength). Germination normally occurs in the dark over an about 12 toabout 14 day period.

Hypocotyl and/or cotyledons are preferably excised from the germinatedseed, subdivided or cut into segments and cultured on a first callusgrowth medium such as an MS medium supplemented with growth substances.The presently preferred medium is the MS medium supplemented with about0.4 mg/l thiamine hydrochloride, about 30 g/l glucose, about 2 mg/l NAA,about 1 mg/l kinetin, a common growth regulator, and about 100 mg/linositol and agar. Thiamine hydrochloride can generally range inconcentration from 0.1 to about 0.5 mg/l, glucose about 20 to about 30g/l, about 1 to about 10 mg/l NAA, about 1 to about 2 mg/l kinetin andabout 50 to about 100 mg/l inositol.

The cultures are maintained at a temperature of about 25 to about 35°C., preferably about 30° C. and with a light/dark cycle of about 16hours of light and about 8 hours of dark. It is preferred to have alight intensity of about 2000 to 4000 lux, more preferably about 3000 to4000 lux.

The calli formed are periodically subcultured at 3 to 4 week intervalsand transferred to a fresh first callus growth medium. In the culturingof the explants, secretions of phenolic compounds from the explants canoccur as evidenced by darkening of the cultured medium. In thisinstance, the medium is changed more regularly. Darkening has beenavoided by changing the culture medium every 10 days. Normally, afterthree to five medium changes, phenolic secretions will disappear. Whenthis occurs, the first callus growth medium can be replaced by freshcallus growth medium containing sucrose or supplemented with sucrose asa carbon source.

After 3 to 4 weeks of culture, active calli develop on the cut surfacesof the explants. The calli are then transferred to a fresh second callusgrowth maintenance medium which is preferably an MS medium combined withabout 1 to about 10 mg/l, preferably about 1 to about 5 mg/l NAA.Cytokinin is employed at a concentration of from 0 to about 1 g/l. Acallus growth medium is characterized as a high salt content mediumcontaining as much as 10 times more salt than the seed germinationmedium. The essential difference between first and second callus growthmedium is the carbon source. Glucose is used during period of phenolicsecretions. Sucrose is used when secretion have stopped. The balance ofthe callus growth medium can remain the same or changed.

The calli are transferred in regular intervals to a fresh callus growthmedium and, after generally about 5 to 7 passages or until ananthocyanin pigmentation becomes evident in a portion of the calli,which is followed by development of a yellowish-white embryogeniccallus.

The embryogenic callus are then selectively subcultured and maintainedby regular subculturing. The embryogenic callus contain somatic embryosat various stages of development. Some may have reached the point ofdevelopment that enables growth into small plantlets. Most, however,require further development. Some may be advanced to germination. Othermay be maintained as a source of embryos for future use.

With reference to FIG. 2, there is illustrated this stage of developmentshowing calli of Acala cotton 10 with somatic embryos 12 of differingsize with some having emerging leaves 14 and roots 16. FIG. 3illustrates a somatic embryo isolated at a late globular stage.

With reference to FIG. 4, further development may be achieved bytransferring the somatic embryos to a third growth medium termed hereinan embryo germination medium, a medium rich in nitrogen usually in theform of ammonia or its equivalent. Suitable media include Beasley andTing's medium, preferably supplemented with up to about 500 mg/l caseinhydrolysate.

Germination occurs from somatic embryos and, within 2 to 3 weeks, a welldeveloped plantlet 18 of up to 6 leaves and good root system isgenerally formed.

At this stage, the plantlets are transferred to soil in small clumps andgrown in a standard incubator under conditions of high humidity.Temperature is normally maintained at about 25 to 30° C. (See FIG. 7).

After a period of growth, the small plants are transferred to largerpots in a greenhouse and thereafter transferred to field and grown tomaturity. All the regenerated plants are preferably self-pollinatedeither while growing in the green house or in field conditions and theseeds collected. Seeds are then germinated and 4 to 5 week old seedlingstransferred to the field for progeny row trials and other standard plantbreeding procedures. Practicing the above procedure produces viablecotton plants from about 35% of the explants in the period of time fromabout 6 to about 8 months.

Proliferation of Embryogenic Cotton Cells In Suspension Cultures

As an alternative to allowing the growing embryogenic calli to bedeveloped into a plant, the callus may be cut into smaller pieces andfurther developed using suspension culture techniques.

In this procedure, suspension concentration is normally from about 750to 1000 mg of callus parts to 8 ml callus growth medium such as thesecond callus growth medium (MS medium supplemented with NAA), andallowed to grow in suspension. In a preferred embodiment, the suspensionof the callus is inserted in T-tubes and placed on a roller drumrotating at about 1.5 rpm under a light regime of about 16 hours oflight and about 8 hours of dark. Growth is for about 3 to 4 weeks.

After about every 3 to 4 weeks, the suspension is filtered to removelarge cell clumps of embryogenic callus depicted in groups in FIG. 5 andas isolated at late globular stages as shown in FIG. 6. The filtrate isreturned to a nutrient medium for a 3 to 4 week period of growth. Thisprocedure is repeated over and over with harvesting of large clumps atabout 3 to 4 week intervals, at which time the medium is supplanted inwhole or in part with fresh callus growth medium. Preferably, about 4volumes or more of the fresh medium are added to about one volume ofresidual suspension. It is presently preferred that the filter employedhave a mesh size greater than about 600 microns, preferably greater than800 microns, as it has been observed the cell masses of a particle sizeless than 600 microns will not develop into plants, whereas cell massesgreater than 600 microns and preferably greater than 800 microns haveundergone sufficient differentiation so as to become embryogenic andcapable of developing into viable plants.

Suspension cultures can also be initiated by transferring of embryogeniccalli to a flask, such as a DeLong or Erlenmeyer flask, containing theliquid embryo growth medium in an amount of about 20 ml of MS and NAA ata concentration of 2.0 mg/l. The flask is placed on a gyrotory shakerand is shaken at about 100-110 strokes per minute. After 3 to 4 weeksthe suspension is suitable for filtration as described above to removethe large cell clumps for plant development.

More typically, after the third or fourth subculture, the cellsuspension from the “T” tube or De Long or Erlenmeyer flask is platedonto agar-solidified MS medium containing NAA (2.0 mg/l), or Beasley &Ting's medium containing casein hydrolysate (500 mg/l) media and asource of nitrogen. Within 3-4 weeks embryogenic calli with developingembryos become visible. Likewise, the larger cell clumps when plated onthe above media give rise to embryogenic clumps with developing embryos.

In both suspension growth methods, the MS media is used to promoteand/or sustain embryos whereas the germination medium is employed forrapid plant development.

The seedling explants, if desired, can be transformed. In thisprocedure, cotyledon and/or hypocotyl segments of the sterilized seedcan be used. Cotyledons are preferred.

The segments are placed in a medium containing an Agrobacterium vectorcontaining a code (genetic marker) such as resistance to an antibiotic,such as for instance kanamycin for a time sufficient for the vector totransfer the gene to the cells of the explant. Generally, contact timesranging from 1 minute to 24 hours may be used and may be accompaniedwith intermittent or gentle agitation. The explants are then removed andplaced on agar-solidified callus growth medium such as a MS mediumsupplemented with NAA (2 mg/l) and incubated about 15 to 200 hours at 25to 35° C., preferably 30° C., on a 16:8 hour light:dark regime.

After incubation, the explants are transferred to the same mediumsupplemented with the antibiotic cefotaxime preferably in aconcentration of 200 mg/l. Cefotaxime is included to prevent anyremaining Agrobacterium from proliferating and overgrowing the planttissues. Alternatively, the explants can be rinsed with MS mediumsupplemented with NAA (2 mg/l) and incubated an additional 4 to 28 daysbefore rinsing, then incubating the same medium containing cefotaxime.At the end of 4-5 weeks of culture on fresh medium, the developingcallus, i.e., primary callus, is separated from the remainder of theprimary explant tissue and transferred to MS medium containing NAA (2mg/l), cefotaxime (200 mg/l) and an antibiotic such as kanamycin sulfate(50 mg/l). Transformed primary callus, identified by virtue of itsability to grow in the presence of the antibiotic (kanamycin), isselected and embryos developed, germinated and plants obtained followingthe procedure set forth above.

It is also feasible to achieve transformation of a cell suspension.Following a normal subculture growth cycle of 7 to 14 days, usually 7 to10 days, cells are allowed to settle leaving a supernatant which isremoved. The remaining concentrated suspended cells may be centrifugedat 4000×g for 5 minutes and the excess medium is discarded. Theconcentrated suspension cultures are resuspended in the 8 ml of the samemedium which contains the Agrobacterium. The suspension is transferredto “T” tubes and suitably agitated for incubation.

Following about 2 to 24 hours, preferably 3 to 5 hours, of incubation toallow for bacterial attachment and DNA transfer, the suspension isremoved and allowed to settle. The supernatant containing the bacteriais discarded and the cells are washed with fresh medium. The suspensionmay, if desired, be centrifuged for about 5 minutes and the supernatantremoved. In either event, the cells are resuspended in the same mediumand transferred to a “T” tube or flask and suspension subcultureresumed. The object is to minimize the amount of unattachedAgrobacterium vector left in the cell suspension.

After about 15 to about 200 hours, typically 15 to about 72 hours,preferably 18 to 20 hours, the suspension is filtered to remove largeclumps and washed with fresh liquid medium and allowed to settle. Thesuspension is resuspended in the fresh liquid medium containingcefotaxime (200 mg/l ) plated on a solidified medium in Petri dishes.

Alternatively, the suspension may be resuspended in fresh mediumcontaining cefotaxime and allowed to grow an additional 4 to 28 daysprior plating on solidified medium in Petri dishes. Cell concentrationis 1 vol. of suspension cells plus 3 vol. of medium with cefotaxime.Kanamycin at 10 to 300 mg/l preferably about 20 to 200 mg/l morepreferably about 40 to 80 mg/l is included in the medium for selectionof transformed cells expressing the neomycin phosphotransferase (NPT)gene. Cells and embryos proliferating in the selective concentration ofkanamycin are further grown as set forth above to mature somatic embryoscapable of germinating and regenerating into whole plants according tothe procedures described herein.

Using the above procedure and with reference to FIG. 9, there is shownvariable cell colonies which is consequence of transformation. Thereexists cotton cells 20 exhibiting resistance to the antibiotickanamycin. With reference to FIG. 10, transformed calli are showndeveloping into somatic embryos on an antibiotic MS medium. FIG. 11exemplifies transformed somatic embryos established to have kanamycinresistance and transformed to have resistance to the herbicideglyhosate. FIG. 12 exemplifies cotton plants obtained by inoculatingtissues with Agrobacterium containing a mutant AroA gene and thereaftergrowing the tissues on non-selective media. FIG. 13 shows germinatingsomatic embryos of variety B1644 obtained from suspension culturestreated with the vector pCIB10/BTA-5, and selected on kanamycin (50mg/L) or G418 (25 mg/L) supplemented media. FIG. 14 shows plantletsdeveloped from the embryos of FIG. 13. FIG. 15 shoes a plantlet of thevariety Siokra developed from transformed embryos exhibiting aresistance to kanamycin.

COTTON REGENERATION EXAMPLE 1 Regeneration of Plants Starting FromCotyledon Explants

Seeds of Acala cotton variety SJ2 of Gossypium hirsutum were sterilizedby contact with 95% alcohol for three minutes, then twice rinsed withsterile water and immersed with a 15% solution of sodium hypochloritefor 15 minutes, then rinsed in sterile water. Sterilized seeds weregerminated on a basal agar medium in the dark for approximately 14 daysto produce a seedling. The cotyledons of the seedlings were cut intosegments of 2-4 mm² which were transferred aseptically to a callusinducing medium consisting of Murashige and Skoog (MS) major and minorsalts supplemented with 0.4 mg/l thiamine-HCl, 30 g/l glucose, 2.0 mg/lNAA, 1 mg/l kinetin, 100 mg/l of m-inositol, and agar (0.8% w/v). Thecultures were incubated at about 30° C. under conditions of 16 hourslight and 8 hours darkness in a Percival incubator with fluorescentlights (cool daylight) providing a light intensity of about 2000-4000lux.

Calli were formed on the cultured tissue segments within 3 to 4 weeksand were white to gray-greenish in color. The calli formed weresubcultured every three to four weeks onto a callus growth mediumcomprising MS medium containing 100 mg/l m-inositol, 20 g/l sucrose, 2mg/l NAA and agar. Somatic embryos formed four to six months after firstplacing tissue explants on a callus inducing medium. The callus andembryos were maintained on a callus growth medium by subculturing ontofresh callus growth medium every three to four weeks.

Somatic embryos which formed on tissue pieces were explanted either tofresh callus growth medium, or to Beasley & Ting's medium (embryogermination medium).

The somatic plantlets which were formed from somatic embryos weretransferred onto Beasley and Ting's medium which contained 1200 mg/lammonium nitrate and 500 mg/l casein hydrolysate as an organic nitrogensource. The medium was solidified by a solidifying agent (Gelrite) andplantlets were placed in Magenta boxes.

The somatic embryos developed into plantlets within about three months.The plantlets were rooted with six to eight leaves and about three tofour inches tall and were transferred to soil and maintained in anincubator under high humidity for three to four weeks and thentransferred to a greenhouse. After hardening, plants were alsotransferred to open tilled soil.

EXAMPLE 2

The procedure of Example 1 was repeated using instead half-strength MSmedium in which all medium components have been reduced to one-half thespecified concentration. Essentially the same results were obtained.

EXAMPLE 3

The procedures of Examples 1 and 2 were repeated except that the explantwas the hypocotyl segments. The same results were obtained.

EXAMPLE 4

The procedure of Examples 1 and 2 were repeated except that the explantwas the immature zygotic embryo. Essentially the same results wereobtained.

EXAMPLE 5

The procedure of Examples 1 and 2 was repeated with Acala cottonvarieties SJ4, SJ5, SJ2C-1, GC510, B1644, B 2724, B1810, the pickervariety Siokra and the stripper variety FC2017. All were successfullyregenerated.

EXAMPLE 6

The procedure of Example 1 was repeated to the extent of obtainingcallus capable of forming somatic embryos. Pieces of about 750-1000 mgof actively growing embryogenic callus was suspended in 8 ml units ofliquid suspension culture medium comprised of MS major and minor salts,supplemented with 0.4 mg/l thiamine HCl, 20 g/l sucrose, 100 mg/l ofinositol and naphthaleneacetic acid (2 mg/l) in T-tubes and placed on aroller drum rotating at 1.5 rpm under 16:8 light:dark regime. Lightintensity of about 2000-4500 lux was again provided by fluorescentlights (cool daylight).

After four weeks, the suspension was filtered through an 840 micron sizenylon mesh to remove larger cell clumps. The fraction smaller than 840microns were allowed to settle, washed once with about 20-25 ml of freshsuspension culture medium. This suspension was transferred to T-tubes (2ml per tube) and each tube diluted with 6 ml of fresh suspension culturemedium. The cultures were maintained by repeating the above procedure at10-12 day intervals. Namely, the suspension was filtered and only thefraction containing cell aggregates smaller than 840 microns wastransferred to fresh suspension culture medium. In all instances, thefraction containing cell clumps larger than 840 microns was placed ontothe callus growth medium to obtain mature somatic embryos.

The somatic embryos that were formed on callus growth medium wereremoved and transferred to embryo germination medium and using theprotocol of Example 1 were germinated, developed into plantlets and thenfield grown plants.

EXAMPLE 7

The procedure of Example 6 was repeated except that suspension cultureswere formed by transferring 750-1000 mg of embryogenic calli to a DeLongflask containing 15-20 ml of the MS liquid medium containing 2 mg/l NAA.The culture containing flask was placed on a gyrotory shaker and shakenat 100-110 strokes/minute. After three weeks the suspension was filteredthrough an 840 micron nylon mesh to remove the large cell clumps forplant growth, as in Example 4. The less than 840 micron suspension wasallowed to settle, washed once in the MS liquid medium and resuspendedin 2 to 5 ml of the MS liquid medium. The suspension was subcultured bytransfer to fresh medium in a DeLong flask containing 1-2 ml ofsuspension and 15 ml of fresh MS liquid medium. The cultures aremaintained by repeating this procedure at seven to ten day intervals. Ateach subculture only the less than 840 micron suspension was subculturedand the large clumps (840 microns or greater) were used for plantgrowth.

EXAMPLE 8

After three or four subcultures using the suspension growth procedure ofExamples 6 and 7, 1.5 to 2.0 ml of cell suspension from the T-tube andDeLong flask were in each instance plated onto agar-solidified MS mediumcontaining 2 mg/l NAA and Beasley & Ting medium containing 500 mg/lcasein hydrolysate. Within three to four weeks embryogenic calli withdeveloping embryos became visible. Again, the 840 micron or greater cellclumps were plated on the callus growth medium giving rise toembryogenic clumps with developing embryos which ultimately grew intoplants.

EXAMPLE 9

The method of Example 1 was repeated with cotton varieties B1654-26,B1654-43, B3991, Acala Royale, B4894, COKER 315, STONEVILLE 506, FC3027, CHEMBRED B2 and CHEMBRED C4.

EXAMPLE 10

The method of Example 1 was repeated with cotton varieties GC356, GAM1,B638, B5002, STONEVILLE 825, HBX87, SICALA, PIMA S6, ORO BLANCO PIMAexcept plants were not obtained from the somatic embryos.

EXAMPLE 11

The method of Example 1 was repeated with cotton varieties Acala Maxxa,Acala Prema, B2086, FC 3027, DP50, DP61, DP90, DP77, DES119, McN235,HBX191, HBX107, CHEMBRED A1, CHEMBRED A2, CHEMBRED A3, CHEMBRED A4,CHEMBRED B1, CHEMBRED B3, CHEMBRED Cl, CHEMBRED C2, CHEMBRED C3,PAYMASTER 145, HS26 and HS46 except embryos and plants were notdeveloped from the callus.

Below is a summary of the varieties which have been regenerated and thestage to which they have been grown:

REGENERATION Example No. VARIETY C¹ E² P³ Example 1 Acala SJ2 +⁴ + +Example 5 Acala SJ4 + + + Example 5 Acala SJ5 + + + Example 5 AcalaSJ-C1 + + + Example 10 Acala GC356 + + −⁵ Example 5 Acala CG510 + + +Example 5 Acala B1644 + + + Example 9 Acala B1654-26 + + + Example 9Acala B1654-43 + + + Example 9 Acala B3991 + + + Example 10 AcalaGAM1 + + − Example 9 Acala Royale + + + Example 11 Acala Maxxa + − −Example 11 Acala Prema + − − Example 10 Acala B638 + + − Example 5 AcalaB1810 + + + Example 5 Acala B2724 + + + Example 12 Acala B2086 + − −Example 9 Acala B4894 + + + Example 10 Acala B5002 + + − Example 9 COKER315 + + + Example 9 STONEVILLE 506 + + + Example 10 STONEVILLE 825 + + −Example 11 DP50 + − − Example 11 DP61 + − − Example 11 DP90 + − −Example 11 DP77 + − − Example 11 DES119 + − − Example 11 McN235 + − −Example 10 HBX87 + + − Example 11 HBX191 + − − Example 11 HBX107 + − −Example 9 FC 3027 + + + Example 5 FC 2017 + − − Example 11 FC 2005 + − −Example 11 FC C1042-R-9-1 + − − Example 11 CHEMBRED A1 + − − Example 11CHEMBRED A2 + − − Example 11 CHEMBRED A3 + − − Example 11 CHEMBRED A4 +− − Example 11 CHEMBRED B1 + − − Example 9 CHEMBRED B2 + + + Example 11CHEMBRED B3 + − − Example 11 CHEMBRED C1 + − − Example 11 CHEMBRED C2 +− − Example 11 CHEMBRED C3 + − − Example 9 CHEMBRED C4 + + + Example 11PAYMASTER 145 + − − Example 11 HS26 + − − Example 11 HS46 + − − Example5 SIOKRA + + + Example 10 SICALA + + − Example 10 PIMA S6 + + − Example10 ORO BLANCO PIMA + + − ¹Callus ²Embryos ³Plants ⁴+indicates that theindicated tissue was obtained ⁵−indicates that the indicated tissue wasnot obtained

COTTON TRANSFORMATION EXAMPLE 12 Transformation to FormTumorous-Phenotype With Agrobacteria LBA 4434

An Acala cotton suspension culture was subcultured for three to fourmonths in T-tubes with the medium (MS medium. containing 2 mg/l NAA)being changed every seven to ten days. After any medium changethereafter the cells can be allowed to settle and harvested fortransformation. The supernatant was removed by pipeting and cellstransformed with the Agrobacterium strain LBA 4434. The Agrobacteriumstrain LBA 4434 [described in Hoekema et al., Nature 303 179-180 (1983),incorporated herein by reference] contains a Ti plasmid-derived binaryplant transformation system. In such binary systems, one plasmidcontains the T-DNA of a Ti-plasmid, the second plasmid contains thevir-region of a Ti-plasmid. The two plasmids cooperate to effect planttransformation. In the strain LBA 4434, the T-DNA plasmid, pAL1050,contains T_(L) of pTiAch5, an octopine Ti-plasmid and the vir-plasmid instrain LBA4434, pAL4404, contains the intact virulence regions ofpTiAch5 [Ooms et al., Plasmid 7 15-29 (1982), incorporated herein byreference] . Strain LBA 4434 is available from Dr. Robert Schilperoortof the Department of Biochemistry, University of Leiden, TheNetherlands.

The transforming Agrobacterium strain was taken from a glycerol stock,inoculated in a small overnight culture, from which a 50-ml culture wasinoculated the following day. Agrobacteria was grown on YEB mediumcontaining per liter in water adjusted to pH 7.2 with NaOH, 5 g beefextract, 1 g yeast extract, 5 g peptone, 5 g sucrose. After autoclaving,1 ml of 2 M MgCl₂ is added after which antibiotics, as required to killother strains. The absorbance at 600 nm of the 50 ml overnight cultureis read, the culture centrifuged and the formed pellet resuspended inthe plant cell growth medium (MS medium plus NAA at 2 mg/l) to a finalabsorbance at 600 nm of 0.5.

Eight ml of this bacterial suspension of Agrobacterium LBA 4434 wasadded to each T-tube containing the suspension plant cells after removalof the supernatant liquid. The T-tube containing the plant and bacteriacells was agitated to resuspend the cells and returned to a roller drumfor three hours to allow the Agrobacteria to attach to the plant cells.The cells were then allowed to settle and the residual supernatantremoved. A fresh aliquot of growth medium was added to the T-tube andthe suspension allowed to incubate on a roller drum for a period of 18to 20 hours in the presence of any residual Agrobacteria which remained.After this time, the cells were again allowed to settle, the supernatantremoved and the cells washed twice with a solution of growth mediumcontaining cefotaxime (200 μg/ml). After washing, the cells from eachT-tube were resuspended in 10 ml growth medium containing cefotaxime(200 μg/ml in all cases) and 1 ml aliquots of the suspension plated onpetri dishes.

Infected cells grew on the growth medium to which no phytohormones wereadded establishing the tissue had received the wild-type phytohormonegenes in T-DNA. The cells developed tumors, further indicatingtransformation of the cultures.

EXAMPLE 13 Transformation of Cotton to Form a Kanamycin-ResistantNon-Tumorous Phenotype

The suspension culture as obtained in Example 12 is transformed using anAgrobacteria containing the T-DNA which contains binary vector pCIB10[Rothstein el al., Gene 53 153-161 (1987), incorporated herein byreference] as well is the pAL4404 vir-plasmid. The T-DNA of pCIB10contains a chimeric gene composed of the promoter from nopalinesynthase, the coding, region from Tn5 encoding the enzyme neomycinphosphotransferase, and the terminator from nopaline synthase. TheAgrobacteria containing pCIB10 are grown on YEB medium containingkanamycin (50 μg/ml). Transformation is accomplished in the same manneras in Example 12 except that the 1 ml aliquots resulting in cells andAgrobacteria are immediately plated on selective media containing eitherkanamycin (50 μg/ml) or G418 (25 μg/ml). Expression of the nos/neo/noschimeric gene in transformed plant tissue allows the selection of thistissue in the presence of both antibiotics. The existence of transformedtissue is apparent on the selection plates in two to four weeks.Uninfected tissue as well as added control tissue will show no signs ofgrowth, turn brown and die. Transformed tissue grows very well in thepresence of both kanamycin and G418.

At this time, tissue pieces which are growing well arc subcultured tofresh selection medium. Somatic embryos form on these tissue pieces andare explanted to fresh non-selective growth media. When the embryosbegin to differentiate and germinate, i.e., at the point where theybegin to form roots and have two or three leaves, they are transferredto Magenta boxes containing growth medium described in Example 1. Growthis allowed to proceed until the plantlet has six to eight leaves, atwhich time it is removed from the agar medium.

The plantlets are now placed in potting soil, covered with a beaker tomaintain humidity and placed in a Percival incubator for four to eightweeks. At this time, the plant is removed from the beaker andtransferred to a greenhouse. The plants grow in the greenhouse, flowerand set seed.

EXAMPLE 14

The procedure of Example 13 was followed, except that the transformingAgrobacteria used contained the T-DNA vector DEI PEP10 as well as thepAL4404 vir plasmid. DEI PEP10, shown in FIG. 33, utilizes two T-DNAPstI cleaved right border sequences from A. tumefaciens (strain C-58)which had been further subdivided with BamHI for integration in theplant genome, a passenger maize phosphoenolpyruvate carboxylase gene(Pepcase gene), and a chimeric gene (NOS/NPT/TK) capable of expressionin plants and conferring resistance to the antibiotics kanamycin andG418. This chimeric gene utilizes a nopaline synthetase promoter, theneomycin phosphotransferase II coding region from Tn5, and theterminator from the herpes simplex virus thymidine kinase gene.Following transformation, embryogenic callus and embryos were obtainedby selection on kanamycin (50 mg/l). No resistant callus was obtainedfrom the control (non-transformed callus) plated on kanamycin at thislevel (50 mg/l).

EXAMPLE 15 Transformation of Cotton Suspension Culture Cells to aGlyphosate-Tolerant Phenotype

The procedure of Example 13 was followed, except that the transformingAgrobacteria used contained the T-DNA vector pPMG85/587 [Fillatti etal., Mol. Gen. Genet. 206 192-199 (1987) incorporated herein byreference] as well as the pAL4404 vir plasmid. The plasmid pPMG85/587carries three chimeric genes capable of expression inplants. Two genescode for neomycin phosphotransferase (NPT) which confers resistance tothe antibiotics kanamycin and G418. The third chimeric gene, containingthe coding sequence from a mutant aroA gene of S. typhimurium, conferstolerance to the herbicide glyphosate [Comai et al., Science 221 370-371(1983), incorporated herein by reference]. The Agrobacteria containingpPMG85/587 were grown on medium containing kanamycin (100 μg/ml).Transformation is accomplished as detailed in Example 13 except that thesuspension is allowed to grow for 28 days at which time 1 ml aliquotswere plated on medium containing selective antibiotics. Expression ofthe NPT chimeric gene in transformed plant tissue allowed selection ofthis tissue on both antibiotics. In this instance the selectiveantibiotic was kanamycin (50 μg/ml).

In two to four weeks, transformed tissue became apparent on theselection plates. Plant tissue, individual embryos and callus were thenplaced on growth medium containing the herbicide glyphosate 1 mM andtransformed tissue continued to grow well. Extraction and analysis ofthe proteins of both callus and embryos confirmed the presence of theproduct of the glyphosate tolerance gene.

EXAMPLE 16 Transformation of Cotton Suspension Culture Cells to aHygromycin-Resistant Non-Tumorous Phenotype

The transformation procedure of Example 13 was followed except there wasused as the transforming Agrobacteria one containing the T-DNA binaryvector pCIB715 [Rothstein et al. Gene 53 153-161 (1987)] as well as thevir plasmid. The T-DNA of pCIB715 contains a chimeric gene composed ofthe promoter and terminator from the cauliflower mosaic virus (CaMV) 35Stranscript [Odell et al., Nature 313 810-812 (1985), incorporated hereinby reference] and the coding sequence for hygromycin Bphosphotransferase [Gritz et al., Gene 25 179-188 (1983) incorporatedherein by reference]. Agrobacteria containing pCIB715 was grown on YEBcontaining kanamycin (50 gg/ml).

Transformation was accomplished as detailed in Example 14 again with thechange that the 1 ml aliquots were plated immediately on mediumcontaining as the selective antibiotic 50 μg/ml hygromycin. Expressionof the chimeric hygromycin gene in transformed plant tissue allows theselection of this tissue on the medium containing hygromycin.Transformed tissue was grown in the manner described in Example 8 on theselection growth medium establishing transformation had occurred.

EXAMPLE 17 Transformation of Cotton Suspension Culture Cells to ConferResistance to Lepidopteran Insects

The procedure of Example 14 was followed except where changes are notedbelow. Different transforming Agrobacteria were used. Also, after planttissue was selected on an antibiotic for the selection of transformedmaterial, it was further selected for expression of the BT gene asdefined herein.

The Agrobacteria used contained the T-DNA vector pCIB10 [Rothstein etal., Gene 53 153-161 (1987) incorporated herein by reference] into whichhad been inserted the following chimeric Bacillus thuringiensisendotoxin genes (“BT Genes”):

To prepare the Agrobacterium vector there was fused the CaMV gene VIpromotor and protoxin coding sequences. A derivative of phage vectormp19 [Yanish-Perron et al., 1985] was first constructed. The steps areshown in FIGS. 16 and 17. First, a DNA fragment containing approximately155 nucleotides 5′ to the protoxin coding region and the adjacentapproximately 1346 nucleotides of coding sequence are inserted intomp19. Phage mp19 ds rf (double-stranded replicative form) DNA wasdigested with restriction endonucleases SacI and SmaI and theapproximately 7.2-kb (kilobase pairs) vector fragment was purified afterelectrophoresis through low-gelling temperature agarose by standardprocedures. Plasmid pKU25/4, containing approximately 10 kb of Bacillusthuringiensis DNA, including the protoxin gene, was obtained from Dr. J.Nueesch, CIBA-Geigy Ltd., Basle, Switzerland. The nucleotide sequence ofthe protoxin gene present in plasmid pKU25/4 is shown in SEQ ID NO: 1below. Plasmid pKU25/4 DNA was digested with endonucleases HpaI andSacI, and a 1503 bp fragment containing nucleotides 2 to 1505 of SEQ IDNO: 1 and purified. This fragment contains approximately 155 bp ofbacteria promotor sequences and approximately 1346 bp of the start ofthe protoxin coding sequence. Approximately 100 ng of each fragment isthen mixed, T4 DNA ligase added, and incubated at 15° C. overnight. Theresulting mixture was transformed into E. coli strain HB101, mixed withindicator bacteria E. coli JM101 and plated. One phage (mpl9/bt) wasused for further construction below.

Next, a fragment of DNA containing the CaMV gene VI promotor, and someof the coding sequences for gene VI, was inserted into mp19/bt. Phagemp19/bt ds rf DNA is digested with BamHI, treated with the largefragment of DNA polymerase to create flush ends and recleaved withendonuclease PstI. The larger vector fragment was purified byelectrophoresis as described above. Plasmid pABD1 [described inPaszkowski et al., EMBO J. 3 2717-2722 (1984) incorporated herein byreference]. Plasmid pABD1 DNA is digested with PstI and HindIII. Thefragment approximately 465 bp long containing the CaMV gene VI promotorand approximately 75 bp of gene VI coding sequence was purified. The twofragments were ligated and plated as described above. One of theresulting recombinant phages, mp19/btca contained the CaMV gene VIpromotor sequences, a portion of the gene VI coding sequence,approximately 155 bp of Bacillus thuringiensis DNA upstream of theprotoxin coding sequence, and approximately 1346 bp of the protoxincoding sequence. To fuse the CaMV promotor sequences precisely to theprotoxin coding sequences, the intervening DNA was deleted usingoligonucleotide-directed mutagenesis of mp19/btca DNA. A DNAoligonucleotide with the sequence 5′-TTCGGATTGTTATCCATGGTTGGAGGTCTGA-3′was synthesized by routine procedures using an Applied Biosystems DNASynthesizer. This oligonucleotide is complimentary to those sequences inphage mp19/btca DNA at the 3′ end of the CaMV promotor [nucleotides 5762to 5778 see Hohn Current Topics in Microbiology and Immunology 96193-235 (1982) incorporate herein by reference] and the beginning of theprotoxin coding sequence (nucleotides 156 to 172 in formula I above).The general procedure for the mutagenesis is that described in Zoller etal. [Methods in Enzymology 100 468-500 (1983) incorporated herein byreference]. Approximately five micrograms of single-stranded phagemp19/btca DNA was mixed with 0.3 mg of phosphorylated oligonucleotide ina volume of 40 μl. The mixture was heated to 65° C. for 5 min, cooled to50° C., and slowly cooled to 4° C. Next, buffer, nucleotidetriphosphates, ATP, T₄ DNA ligase and large fragment of DNA polymerasewere added and incubated overnight at 15° C. as described by Zoller etal. [Methods in Enzymology 100 468-500 (1983) incorporated herein byreference]. After agarose gel electrophoresis, circular double-strandedDNA was purified and transfected into E. coli strain JM101. Theresulting plaques are screened for sequences that hybridize with32P-labeled oligonucleotide, and phage are analyzed by DNA restrictionendonuclease analysis. Among the resulting phage clones were ones whichhave correctly deleted the unwanted sequences between the CaMV gene VIpromotor and the protoxin coding sequence. This phage is calledmp19/btca/del (see FIG. 17).

Next, a plasmid was constructed in which the 3′ coding region of theprotoxin gene was fused to CaMV transcription termination signals. Thesteps are shown in FIG. 18. First, plasmid PABDI DNA was digested withendonucleases 35 BamHI and BglII and a 0.5 kb fragment containing theCaMV transcription terminator sequences isolated. Next plasmid pUC19[Yanisch-Perron et al., Gene 33 103-119 (1985) incorporated herein byreference] was digested with BamHI, mixed with the 0.5 kb fragment andincubated with T₄ DNA ligase. After transformation of the DNA into E.coli strain HB101, one of the resulting clones, called plasmid p702, wasobtained which has the structure shown in FIG. 18. Next, plasmid p702DNA was cleaved with endonucleases SacI and SmaI, and the larger,approximately 3.2 kb fragment isolated by gel electrophoresis. PlasmidpKU25/4 DNA was digested with endonucleases AhaIII and SacI, and the2.3-kb fragment (nucleotides 1502 to 3773 of SEQ ID NO: 1) containingthe 3′ portion of the protoxin coding sequence (nucleotides 1504 to 3773of SEQ ID NO: 1) was isolated after gel electrophoresis. These two DNAfragments are mixed, incubated with T₄ DNA ligase and transformed intoE. coli strain HB101. The resulting plasmid was p702/bt (FIG. 18).

Finally, portions of phage mp19/btca/del ds rf DNA and plasmid p702/btwere joined to create a plasmid containing the complete protoxin codingsequence flanked by CaMV promoter and terminator sequences (see FIG.18). Phage mp19/btca/del DNA was digested with endonucleases SacI andSphI, and a fragment of approximately 1.75 kb is purified followingagarose gel electrophoresis. Similarly, plasmid p702/bt DNA is digestedwith endonucleases SacI and SalI and a fragment of approximately 2.5 kbis isolated. Finally, plasmid pBR322 DNA [Bolivar et al., Gene 2 95-113(1977) incorporated herein by reference] was digested with SalI and SphIand the larger 4.2-kb fragment isolated. All three DNA fragments weremixed and incubated with T4 DNA ligase and transformed into E. colistrain HB101. The resulting plasmid, pBR322/bt14 is a derivative ofPBR322 containing the CaMV gene VI promoter and translation startsignals fused to the Bacillus thuringiensis crystal protein codingsequence, followed by CaMV transcription termination signals (shown inFIG. 19).

The vector pCIB10 is a Ti-plasmid-derived vector useful for transfer ofthe chimeric gene to plants via Agrobacterium tumefaciens. The vector isderived from the broad host range plasmid pRK252, which may be obtainedfrom Dr. W. Barnes, Washington University, St. Louis, Mo. The vectoralso contains a gene for kanamycin resistance in Agrobacterium, fromTn903, and left and right T-DNA border sequences from the Ti plasmidpTiT37. Between the border sequences are the polylinker region from theplasmid pUC18 and a chimeric gene that confers kanamycin resistance inplants.

First, plasmid pRK252 was modified to replace the gene conferringtetracycline-resistance with one conferring resistance to kanamycin fromthe transposon Tn903 [Oka et al., J. Mol. Biol. 147 217-226 (1981)incorporated herein by reference], and was also modified by replacingthe unique EcoRI site in pRK252 with a BglII site (see FIG. 20 for asummary of these modifications). Plasmid pRK252 was first digested withendonucleases SalI and SmaI, then treated with the large fragment of DNApolymerase I to create flush ends, and the large vector fragmentpurified by agarose gel electrophoresis. Next, plasmid p368 was digestedwith endonuclease BamHI, treated with the large fragment of DNApolymerase, and an approximately 1050-bp fragment isolated after agarosegel electrophoresis; this fragment containing the gene from transposonTn903 which confers resistance to the antibiotic kanamycin [Oka et al.,J. Mol. Biol. 147 217-226 (1981) incorporated herein by reference]. Bothfragments were then treated with the large fragment of DNA polymerase tocreate flush ends. Both fragments are mixed and incubated with T4 DNAligase overnight at 150C. After transformation into E. coli strain HB101and selection for kanamycin resistant colonies, plasmid pRK252/Tn903 isobtained (see FIG. 19).

Plasmid pRK252/Tn903 was digested at its EcoRI site, followed bytreatment with the large fragment of E. coli DNA polymerase to createflush ends. This fragment was added to synthetic BglII restriction sitelinkers, and incubated overnight with T₄ DNA ligase. The resulting DNAwas digested with an excess of BglII restriction endonuclease and thelarger vector fragment purified by agarose gel electrophoresis. Theresulting fragment was again incubated with T4 DNA ligase torecircularize the fragment via its newly-added BglII cohesive ends.Following transformation into E. coli strain HB101, plasmidpRK252/Tn903/BglII is obtained (see FIG. 20).

A derivative of plasmid pBR322 was constructed which contains the Tiplasmid T-DNA borders, the polylinker region of plasmid pUC19, and theselectable gene for kanamycin resistance in plants (see FIG. 21).Plasmid pBR325/Eco29 contains the 1.5-kb EcoRI fragment from thenopaline Ti plasmid pTiT37. This fragment contains the T-DNA left bordersequence [Yadav et al., Proc. Natl. Acad. Sci. USA 79 6322-6326 (1982)incorporated herein by reference]. To replace the EcoRI ends of thisfragment with HindIII ends, plasmid pBR325/Eco29 DNA was digested withEcoRI, then incubated with nuclease Sl, followed by incubation with thelarge fragment of DNA polymerase to create flush ends, then mixed withsynthetic HindIII linkers and incubated with T4 DNA ligase. Theresulting DNA was digested with endonucleases ClaI and an excess ofHindIII, and the resulting 1.1-kb fragment containing the T-DNA leftborder purified by gel electrophoresis. Next, the polylinker region ofplasmid pUC19 was isolated by digestion of the plasmid DNA withendonucleases EcoRI and HindIII and the smaller fragment (approximately53 bp) isolated by agarose gel electrophoresis. Next, plasmid pBR322 wasdigested with endonucleases EcoRI and ClaI, mixed with the other twoisolated fragments, incubated with T4 DNA ligase and transformed into E.coli strain HB101. The resulting plasmid, pCIB5, contains the polylinkerand T-DNA left border in a derivative of plasmid pBR322 (see FIG. 21).

A plasmid containing the gene for expression of kanamycin resistance inplants was constructed (see FIGS. 22 and 23). Plasmid Bin6 obtained fromDr. M. Bevan, Plant Breeding Institute, Cambridge, UK. This plasmid isdescribed in the reference by Bevan [Nucl. Acids Res. 12 8711-8721(1984) incorporate herein by reference]. Plasmid Bin6 DNA was digestedwith EcoRI and HindIII and the fragment approximately 1.5 kb in sizecontaining the chimeric neomycin phosphotransferase (NPT) gene isisolated and purified following agarose gel electrophoresis. Thisfragment was then mixed with plasmid pUC18 DNA which had been cleavedwith endonucleases EcoRI and HindIII. Following incubation with T4 DNAligase, the resulting DNA was transformed into E. coli strain HB101. Theresulting plasmid is called pUC18/neo. This plasmid DNA containing anunwanted BamHI recognition sequence between the neomycinphosphotransferase gene and the terminator sequence for nopalinesynthase [see Bevan Nucl. Acids Res. 12 8711-8721 (1984) incorporatedherein by reference]. To remove this recognition sequence, plasmidpUC18/neo was digested with endonuclease BamHI, followed by treatmentwith the large fragment of DNA polymerase to create flush ends. Thefragment was then incubated with T4 DNA ligase to recircularize thefragment, and transformed into E. coli strain HB101. The resultingplasmid, pUC18/neo(Bam) has lost the BamHI recognition sequence.

The T-DNA right border sequence was then added next to the chimeric NPTgene (see FIG. 24). Plasmid pBR325/Hind23 contains the 3.4-kb HindIIIfragment of plasmid pTiT37. This fragment contains the right T-DNAborder sequence [Bevan et al., Nucl. Acids Res. 11 369-385 (1983)incorporated herein by reference]. Plasmid pBR325/Hind23 DNA was cleavedwith endonucleases SacII and HindIII, and a 1.0 kb fragment containingthe right border isolated and purified following agarose gelelectrophoresis. Plasmid pUC18/neo (Bam) DNA was digested withendonucleases SacII and HindIII and the 4.0 kb vector fragment isolatedby agarose gel electrophoresis. The two fragments were mixed, incubatedwith T4 DNA ligase and transformed into E. coli strain HB101. Theresulting plasmid, pCIB4 (shown in FIG. 23), contains the T-DNA rightborder and the plant selectable marker for kanamycin resistance in aderivative of plasmid pUC18.

Next, a plasmid was constructed which contains both the T-DNA left andright borders, with the plant selectable kanamycin-resistance gene andthe polylinker of pUC18 between the borders (see FIG. 28). Plasmid pCIB4DNA was digested with endonuclease HindIII, followed by treatment withthe large fragment of DNA polymerase to create flush ends, followed bydigestion with endonuclease EcoRI. The 2.6-kb fragment containing thechimeric kanamycin-resistance gene and the right border of T-DNA wasisolated by agarose gel electrophoresis. Plasmid pCIBS DNA was digestedwith endonuclease AatII, treated with T4 DNA polymerase to create flushends, then cleaved with endonuclease EcoRI. The larger vector fragmentwas purified by agarose gel electrophoresis, mixed with the pCIB4fragment, incubated with T4 DNA ligase, and transformed into E. colistrain HB101. The resulting plasmid, pCIB2 (shown in FIG. 24) is aderivative of plasmic pBR322 containing the desired sequences betweenthe two T-DNA borders.

The following steps complete construction of the vector pCIB10, and areshown in FIG. 25. Plasmid pCIB2 DNA was digested with endonucleaseEcoRV, and synthetic linkers containing BglII recognition sites areadded as described above. After digestion with an excess of BglIIendonuclease, the approximately 2.6-kb fragment was isolated afteragarose gel electrophoresis. Plasmid pRK252/Tn903/BglII, described above(see FIG. 20) was digested with endonuclease BglII and then treated withphosphatase to prevent recircularization. These two DNA fragments aremixed, incubated with T4 DNA ligase and transformed into E. coli strainHB101. The resulting plasmid is the completed vector, pCIB10.

Insertion of the chimeric protoxin gene into vector pCIB10 is by thesteps shown in FIG. 26. Plasmid pBR322/bt14 DNA was digested withendonucleases PvuI and SalI, and then partially digested withendonuclease BamHI. A BamHI-SalI fragment approximately 4.2 kb in size,containing the chimeric gene, was isolated following agarose gelelectrophoresis, and mixed with plasmid pCIB10 DNA which had beendigested with endonucleases BamHI and SalI. After incubation with T4 DNAligase and transformation into E. coli strain HB101, plasmid shown inFIG. 26 and contained the chimeric protoxin gene in the plasmid vectorpCIB10.

In order to transfer plasmid pCIB10/19Sbt from E. coli HB101 toAgrobacterium, an intermediate E. coli host strain S17-1 was used. Thisstrain, obtainable from Agrigenetics Research Corp., Boulder, Colo.contains mobilization functions that transfer plasmid pCIB10 directly toAgrobacterium via conjugation, thus avoiding the necessity to transformnaked plasmid DNA directly into Agrobacterium [reference for strainS17-1 is Simon et al., “Molecular Genetics of the Bacteria-PlantInteraction”, A Puhler, ed., Springer Verlag, Berlin, pages 98-106(1983) incorporated herein by reference]. First, plasmid pCIB10/19SbtDNA is introduced into calcium chloride-treated S17-1 cells. Next,cultures of transformed S17-1 cells and Agrobacterium tumefaciens strainLBA4404 [Ooms et al., Gene 14 33-50 (1981) incorporated herein byreference] were mixed and mated on an N agar (Difco) plate overnight atroom temperature. A loopful of the resulting bacteria are streaked ontoAB minimal media [Chilton et al., Proc. Natl. Acad. Sci. USA 777347-7351 (1974) incorporated herein by reference] plated with 50 μg/mlkanamycin and incubated at 28° C. Colonies were restreaked onto the samemedia, then restreaked onto NB agar plates. Slow-growing colonies werepicked, restreaked onto AB minimal media with kanamycin and singlecolonies isolated. This procedure selects for Agrobacteria containingthe pCIB10/19SBt plasmid.

Construction of a Bacillus thuringiensis protoxin chimeric gene with theCaMV 35S promoter was achieved by construction of a CaMV 35S PromoterCassette Plasmid pCIB710 was constructed as shown in FIG. 27. Thisplasmid contained CaMV promoter and transcription termination sequencesfor the 35S RNA transcript [Covey et al., Nucl. Acids Res. 9 6735-6747(1981) incorporated herein by reference] . A 1149-bp BglII restrictionfragment of CaMV DNA [Hohn et al. In: Current Topics in Microbiology andImmunology 96 194-220 and Appendices A to G (1982) incorporated hereinby reference] was isolated from plasmid pLVlll (obtained from Dr. S.Howell Univ. San Diego, Calif.; alternatively, the fragment can beisolated directly from CaMV DNA) by preparative agarose gelelectrophoresis as described earlier and mixed with BamHI-cleavedplasmid pUC19 DNA, treated with T4 DNA ligase, and transformed into E.coli. The BamHI restriction site in the resulting plasmid has beendestroyed by ligation of the BglII cohesive ends to the BamHI cohesiveends. The resulting plasmid, called pUC19/35S, was then used inoligonucleotide-directed in vitro mutagenesis to insert the BamHIrecognition sequence GGATCC immediately following CaMV nucleotide 7483in the Hohn reference. The resulting plasmid, pCIB710, contains the CaMV35S promotor region and transcription termination region separated by aBamHI restriction site. DNA sequences inserted into this BamHI site willbe expressed in plants by the CaMV transcription regulation sequencespCIB710 does not contain any ATG translation initiation codons betweenthe start of transcription and the BamHI site.

Insertion of the CaMV 35S promoter/Terminator Cassette into pCIB10occurred by the steps outlined in FIG. 28. Plasmids pCIB10 and pCIB710DNAs were digested with EcoRI and SalI, mixed and ligated. The resultingplasmid, pCIB10/710 has the CaMV 35S promoter/terminator cassetteinserted into the plant transformation vector pCIB10. The CaMV 35Ssequences are between the T-DNA borders in pCIB10, and thus will beinserted into the plant genome in plant transformation.

Insertion of the Bacillus thuringiensis protoxin gene into pCIB10/710occurred by the steps outlined in FIG. 29. As a source of the protoxingene, plasmid pCIB10/19Sbt was digested with BamHI and NcoI, and the3.6-kb fragment containing the protoxin gene was isolated by preparativegel electrophoresis. The fragment was then mixed with syntheticNcoI-BamHI adapter with the sequence 5′ -CATGGCCGGATCCGGC-3′, thendigested with BamHI. This step creates BamHI cohesive ends at both endsof the protoxin fragment. This fragment was then inserted intoBamHI-cleaved pCIB10/710. The resulting plasmid, pCIB10/35Sbt, shown inFIG. 29, contains the protoxin gene between the CaMV 35S promoter andtranscription termination sequences.

Transfer of the plasmid pCIB10/35Sbt into Agrobacterium tumefaciensstrain LBA4404 was as described above.

Construction of a deleted Bacillus thuringiensis protoxin genecontaining approximately 725 amino acids, and construction of a chimericgene containing this deleted gene with the CaMV 35S promoter was made byremoving the COOH-terminal portion of the gene by cleaving at the KpnIrestriction endonuclease site at position 2325 in the sequence shown inSEQ ID NO: 1. Plasmid pCIB10/35Sbt (FIG. 29) was digested with BamHI andKpnI, and the approximately 2.2-kb BamHI/KpnI fragment containing thedeleted protoxin gene isolated by preparative agarose gelelectrophoresis. To convert the KpnI site at the 3′ end to a BamHI site,the fragment was mixed with a KpnI/BamHI adapter oligonucleotide andligated. This fragment is then mixed with BamHI-cleaved pCIB10/710 (FIG.28).

A deleted protoxin gene containing approximately 645 amino acids wasmade by removing the COOH-terminal portion of the gene by cleaving atthe BclI restriction endonuclease site at position 2090 in the sequenceshown in SEQ ID NO: 1. Plasmid pCIB10/35Sbt (FIG. 29) was digested withBamHI and BclI, and the approximately 1.9-kb BamHI/BcII fragmentcontaining the deleted protoxin gene isolated by preparative agarose gelelectrophoresis. Since BclI creates a cohesive end compatible withBamHI, no further manipulation is required prior to ligating thisfragment into BamHI-cleaved pCIB10/710 (FIG. 28). The resulting plasmid,which has the structure pCIB10/35Sbt(BclI) shown in FIG. 31 was selectedon kanamycin.

The resulting transformants, designated pCIB10/35Sbt(KpnI) and shown inFIG. 30, contain the deleted protoxin gene of approximately 725 aminoacids. These transformants are selected on kanamycin.

A deleted protoxin gene was made by introducing a BamHI cleavage site(GGATCC). This is done by cloning the BamHI fragment containing theprotoxin sequence from pCIB10/35Sbt into mp18, and using standardoligonucleotide mutagenesis procedures described above. Aftermutagenesis, double-stranded replicative form DNA is prepared from theM13 clone, which is then digested with BamHI. The approximately 1.9-kbfragment containing the deleted protoxin gene is inserted intoBamHI-cleaved pCIB10/710. The resulting plasmid, which the structurepCIB10/35Sbt(607) shown in FIG. 32 is selected for on kanamycin.

The pCIB10/Sbt 607 was used. Transformation was accomplished as detailedin Example 7 with the change that the 1 ml aliquots were platedimmediately on medium containing selective antibiotics. This selectionmedium contained kanamycin (50 μg/ml) or G418 (25 μg/ml). Expression ofthe NPT chimeric gene in both transformed plant tissue allows theselection of this tissue on-either antibiotic.

In 2-4 weeks, transformed tissue became apparent on the selectionplates. Plant material was selected on kanamycin or G418. Plant tissue(either individual embryos or callus) was then extracted with buffer andassayed for expression of the BT gene product by ELISA assay. Theconditions of extraction are as follows: per 100 mg of tissue,homogenize in 0.1 ml of extraction buffer containing 50 mM NaCO₃ (pH9.5), 0.05% Triton, 0.05% Tween, 100 mM NaCl, 10 mM EDTA, 1 mMleupeptine, and 1 mM PMSF. The leupeptine and PMSF are added immediatelyprior to use from 100×stock solutions. The tissue was ground with amotor driven pestle. After extraction, 2 M Tris pH 7 was added to adjustpH to 8.0-8.5 then centrifuged at 12,000 RPM in a Beckman microfuge 12(10 minutes at 4° C.), and the supernatant saved for enzyme linkedimmunosorbent assay (“ELISA”). ELISA techniques are a general tool[described by Clark et al., Methods in Enzymology 118 742-766 (1986)incorporated by reference].

An ELISA for the Bt toxin was developed using standard procedures andused to analyze transgenic plant material for expression of Btsequences. For this procedure, an ELISA plate is pretreated with ethanoland affinity-purified rabbit anti-Bt antiserum (50 μl) at aconcentration of 3 μg/ml in borate-buffered saline (see below) is addedto the plate. This was allowed to incubate overnight at 4° C. Antiserumwas produced in response to immunizing rabbits with gradient-purified Btcrystals [Ang et al., Appl. Environ. Microbiol. 36 625-626 (1978)),incorporated herein by reference] solubilized with sodium dodecylsulfate and washed with ELISA Wash Buffer (see below). It was thentreated for 1 hour at room temperature with Blocking Buffer (see below)washed with ELISA Wash Buffer. Plant extract was added in an amount togive 50 μg of protein (this is typically about 5 microliters ofextract). Leaf extraction buffer as protein is determined by theBradford method [Bradford Anal. Biochem. 72 248 (1976) incorporatedherein by reference] using a commercially available kit obtained fromBio-Rad, Richmond, Calif. If dilution of the leaf extract is necessary,ELISA Diluent (see below)] is used. Allow this to incubate overnight at4° C. After a wash with ELISA Wash Buffer, 50 μl affinity-purified goatanti-Bt antiserum is added at a concentration of 3 μg/ml protein inELISA Diluent. This is allowed to incubate for 1 hour at 37° C., thenwashed with ELISA Wash Buffer. 50 μl rabbit anti-goat antibody bound toalkaline phosphatase [commercially available from Sigma Chemicals, St.Louis, Mo.] is diluted 1:500 in ELISA Diluent and allowed to incubatefor 1 hour at 37° C., then washed with ELISA Wash Buffer. 50 microliterssubstrate [0.6 mg/ml p-nitrophenyl phosphate in ELISA Substrate Buffer(see below) are added and incubated for 30 minutes at room temperature.Reaction is terminated by adding 50 μl of 3 M NaOH. Absorbance is readat 405 nm in modified ELISA reader [Hewlett Packard, Stanford, Calif.].

Plant tissue transformed with the pCIB10/35SBt(BclI) when assayed usingthis ELISA procedure showed a positive reaction, indicating expressionof the Bt gene.

EPBS (ELISA Phosphate Buffered Saline)  10 mM NaPhosphate Na₂HPO₄  4.68grams/4 liters NaH₂PO₄.H₂O 0.976 grams/4 liters 140 mM NaCl NaCl  32.7grams/4 liters pH should be approximately 7.4

Borate Buffered Saline

100 mM Boric acid

25 mM Na Borate

75 mM NaCl

Adjust pH to 8.4-8.5 with HCl or NaOH as needed.

ELISA Blocking Buffer

In EPBS,

1% BSA

0.02% Na azide

ELISA Wash Buffer

10 mM Tris-HCl pH 8.0

0.05% Tween 20

0.02% Na Azide

2.5 M TRIS

ELISA Diluent

In EPBS:

0.05% Tween 20

1% BSA

0.02% Na Azide

ELISA Substrate Buffer

In 500 ml,

48 ml Diethanolamine,

24.5 mg MgCl₂;

adjust to pH 9.8 with HCl.

ELISA Substrate

15 mg p-nitrophenyl phosphate in 25 ml Substrate Buffer.

For bioassays, cell suspensions from antibiotic-resistant cell culturesobtained from tranformations with the Agrobacteria were initiated.Suspensions were grown in medium supplemented with G418 (25 mg/l), andsubcultured antibiotic-containing medium on 7-10 day intirvals. Samplesof these cultures are used in bioassays to test for toxicity tolepidopterous insects. Twenty ml aliquots of these cultures were allowedto settle (cell volume is about 3-4 ml), and resuspended in mediumlacking antibiotics. Suspensions were then allowed to grow for anadditional two days in this medium to deplete the cells of any residualantibiotic. Two circles of wet Whatman 2.3 cm filter paper were placedin the bottom of a ¾ oz portion cup. A layer of transformed suspensionculture cells 0.2 cm deep was placed onto the filter paper disk. Anewly-hatched Manduca sexta or Heliothis virescens larva was placed intoeach portion cup. Controls were made up of larvae fed on non-transformedsuspension culture cells. Discs were replenished on 2-day intervals oras needed. Manduca larvae generally require more plant material. Thegrowth rate and mortality of the larvae feeding on transformed cellscompared with the growth rate of larvae feeding on untransformed cellsis scored after 5 days, and clearly affirms the toxicity of the BT geneproduct in transformed cotton cells.

EXAMPLE 18 Transformation of Cotton Plants

Plant segments were placed in a medium containing an Agrobacteriumvector containing a selectable marker such as resistance to anantibiotic, kanamycin, for 1 minute to 24 hours to transfer the gene tothe cells of the explant. The explants were then removed and placed onagar-solidified callus growth medium (MS medium supplemented with 2 mg/lNAA and incubated for 15 to 200 hours at 30° C., on a 16:8 hourlight:dark regime.

After incubation, the explants were transferred to the same mediumsupplemented with 200 mg/l cefotaxime to kill any Agrobacterium presentin the culture. At the end of 4-5 weeks of culture on fresh medium, thedeveloping callus was separated from the remainder of the primaryexplant tissue and transferred to MS medium containing 2 mg/l NAA, 200mg/ml cefotaxime and 50 mg/l kanamycin sulfate. Transformed primarycallus was selected.

EXAMPLE 19 Transformation of Cotton Embryos

Embryos were placed in a medium containing an Agrobacterium vectorcontaining resistance to kanamycin for 1 minute to 24 hours to transferthe gene to the cells of the embryos. The embryos were then removed andplaced on agar-solidified callus growth medium (MS medium supplementedwith 2 mg/l NAA and incubated for 15 to 200 hours at 30° C., on a 16:8hour light:dark regime.

After incubation, the embryos were transferred to the same mediumsupplemented with 200 mg/l cefotaxime. At the end of 4-5 weeks ofculture on fresh medium, the embryos were transferred to MS mediumcontaining 2 mg/l NAA, 200 mg/ml cefotaxime and 50 mg/l kanamycinsulfate. Transformed embryos were selected.

EXAMPLE 20 Transformation of Cotton Callus

Callus was placed in a medium containing an Agrobacterium vectorcontaining resistance to kanamycin for 1 minute to 24 hours to transferthe gene to the cells of the embryos. The callus was then removed andplaced on agar-solidified callus growth medium (MS medium supplementedwith 2 mg/l NAA and incubated for 15 to 200 hours at 30° C., on a 16:8hour light:dark regime.

After incubation, the callus is transferred to the same mediumsupplemented with 200 mg/l cefotaxime. At the end of 4-5 weeks ofculture on fresh medium, the developing callus was transferred to MSmedium containing 2 mg/l NAA, 200 mg/ml cefotaxime and 50 mg/l kanamycinsulfate. Transformed callus was selected.

EXAMPLE 21

The method of Examples 18, 19 and 20 were used to transform plants,embryos and callus of the following cotton varieties: SJ2, SJ5, SJ-C1,GC510, B1644, B1654-26, B1654-43, B1810, B2724, COKER 315, STONEVILLE506, CHEMBRED B2, CHEMBRED C4 and SIOKRA.

EXAMPLE 22

The method of Examples 19 and 20 were used to transform embryos andcallus of the following cotton varieties: Acala Royale, FC 3027 andSICALA.

EXAMPLE 23

The method of Example 20 was used to transform callus of the followingcotton varieties: GC356, Acala Maxxa, Acala Prema, B4894, DP50, DP61,DP90 and ORO BLANCO PIMA.

EXAMPLE 24

The method of Example 18 was repeated except kanamycin was used at aconcentration of 5 mg/l.

EXAMPLE 25

The method of Example 18 was repeated except kanamycin was added whenthe explants were transferred to the MS medium supplemented with 200mg/l cefotamine.

EXAMPLE 26

The method of Example 18 was repeated except G418 at a concentration of25 mg/l was used in place of kanamycin.

The transformations are summarized in the Table below.

TRANSFORMATION Example No. VARIETY C¹ E² P³ Example 18 Acala SJ2 + + +Example 18 Acala SJ5 + + + Example 18 Acala SJ-Cl + + + Example 20 AcalaGC356 + − − Example 18 Acala CG510 + + + Example 18 Acala B1644 + + +Example 18 Acala B1654-26 + + + Example 18 Acala B1654-43 + + + Example19 Acala Royale + + − Example 20 Acala Maxxa + − − Example 21 AcalaPrema + − − Example 18 Acala B1810 + + + Example 18 Acala B2724 + + +Example 20 Acala B4894 + − − Example 18 COKER 315 + + + Example 18STONEVILLE 506 + + + Example 20 DP50 + − − Example 20 DPG1 + − − Example20 DP90 + − − Example 19 FC 3027 + + − Example 18 CHEMBRED B2 + + +Example 18 CHEMBRED C4 + + + Example 18 SIOKRA + + + Example 19SICALA + + − Example 20 ORO BLANCO PIMA + − − ¹Callus ²Embryos ³Plants⁴+ indicates that transtormation of the tissue was performed ⁵+indicates that transformation of the tissue was not obtained

EXAMPLE 27

Heliothis virescens eggs laid on sheets of cheesecloth are obtained fromthe Tobacco Insect Control Laboratory at North Carolina StateUniversity, Raleigh, N.C. The cheesecloth sheets are transferred to alarge covered glass beaker and incubated at 29° C. with wet paper towelsto maintain humidity. The eggs hatched within three days. As soon aspossible after hatching, the larvae (one larva per cup) are transferredto covered ¾ oz. plastic cups. Each cup contains cotton leaf discs.Larvae are transferred using a fine bristle paint brush.

Leaf discs one centimeter in diameter are punched from leaves of cottonplants and placed on a circle of wet filter paper in the cup with thelarva. At least 6-10 leaf discs, representing both young and old leaves,are tested from each plant. Leaf discs are replaced at two-dayintervals, or as necessary to feed the larvae. Growth rates [size orcombined weight of all replica worms] and mortality of larvae feeding onleaves of transformed plants are compared with those of larva feeding onuntransformed cotton leaves.

Larvae feeding on discs of cotton transformed with pCIB10/35SB5(BclI)show a decrease in growth rate and increase in mortality compared withcontrols.

It was observed that a certain number of our regenerated plants (5-10%)appeared to have acquired genetically heritable phenotypic variations asa consequence of the process of regeneration. This variation is known assomaclonal variation. The following examples illustrate how somaclonalvariation as a consequence of our regeneration procedure has been usedto introduce commercially useful new traits into cotton varieties.

EXAMPLE 28 Cotton Regenerants Tolerant to Fungal Pathogens

The procedure of Example 1 was followed, and regenerated cotton plantsobtained of the variety SJ5 and SJ4 were hardened and placed in thesoil. These plants were self-pollinated and the seed, representing theF1 generation, collected.

To obtain regenerants (somaclonal variants) more tolerant toVerticillium, the F1 generation was planted in a Verticillium infestedfield for progeny row analysis. Seed of the varieties SJ4 and SJ5 wereplanted in the field as controls. Somaclonal variants more tolerant thanthe parental varieties to the Verticillium fungus were identified in afew of the progeny rows (5%) by assessing overall plant vigor, yield,and the absence of foliar symptoms associated with the disease. FIG. 33shows the progeny rows of regenerants planted in a Verticillium infestedfield. FIG. 34 shows a Verticillium tolerant somaclonal variant ofvariety SJ4. This improvement in tolerance to the fungal pathogen wasfound to be genetically stable and passed on to subsequent generations.

EXAMPLE 29 Cotton Regenerants with Altered Growth Habits

The procedure of Example 28 was followed except that, rather thanplanting in disease-infested soil, the F1 generation was planted in acotton breeding nursery. The overall growth habit of the F1 regeneratedprogeny was compared to that of the control varieties. Somaclonalvariants were identified which were more uniform in growth habit andshorter in stature than the parental variety. One SJ5 regenerant,identified in our trials as Phy 6, was 20% shorter in stature than theparental variety. This kind of growth habit is desirable in cotton grownunder narrow row (30″ row spacing) cultural conditions. These traitswere found to be genetically stable and passed on to subsequentgenerations.

EXAMPLE 30 Cotton Regenerants With Improved Fiber Traits

The procedure of Example 28 was followed except that the F1 progeny ofregenerants were planted in a cotton breeding nursery and allowed to setfruit. When the bolls were mature, the cotton was harvested andsubjected to an analysis of several fiber quality traits includinglength, uniformity, tensile strength, elasticity, and micronaire.Somaclonal variants were identified which were improved significantlyover the parental variety in one or more of these traits. Representativedata from F2 progeny (cell pollination of the F1) are included in thefollowing Table 1. Values marked with an asterisk represent improvementsin SJ5 regenerants which are statistically significant and have beenfound to breed true in subsequent generations.

TABLE 1 Fiber Properties Variety Uniformity Tensile or strain LengthIndex Strength Elasticity Micronaire SJ5 1.13 48.7 24.7 6.8 4.27 3SP161.27* 51.2 24.6 8.0* 4.10* 3SP20 1.28* 53.1* 23.1 7.6* 4.13* 5SP10 1.1153.2* 25.7* 6.2 4.55 5SP17 1.18 51.7 26.7* 7.1 4.43

EXAMPLE 31 Cotton Regenerants With Improved Yield

The procedure of Example 28 was followed except that the F1 progeny ofregenerants of the variety SJ4 were planted in replicated yield trialsalong with nonregenerated controls. One variant, which exhibited a moreuniform growth habit and more vigorous growth habit, yielded 4% morecotton than the parental variety in the same trial. The data are givenin Table 2 below.

TABLE 2 Variety or Ave Yield per Ave Yield % Strain plot (lb) lbs/AcreIncrease SJ4 Control 28.0 3049 Phy 4 29.1 3169 4%* *This difference wassignificant at the 95% confidence level.

A 4% increase in yield would represent a return of almost $20 per acreto the average cotton grower in California, where over one million acresof cotton are grown annually.

EXAMPLE 32 Cotton Regenerants Tolerant to a Herbicide. (Kanamycin)

Suspension cultures of the cotton variety B1644 were developed accordingto the method of Example 5. Suspension cultures were then plated onto anagar medium as described in Example 6, but supplemented with theherbicide (antibiotic) kanamycin (25 mg/l). Most of the cells in thepopulation died, but a few (1 to 5%) were tolerant and survived. Thesewere selectively subcultured onto agar-solidified media supplementedwith increasing concentrations of kanamycin, until the finalconcentration reached 50 mg/l. Embryos were then developed from thiscallus, and those resistant embryos were germinated into kanamycinresistant plants.

1 4360 base pairs nucleic acid double linear DNA (genomic) Bacillusthuringiensis 1 GTTAACACCC TGGGTCAAAA ATTGATATTT AGTAAAATTA GTTGCACTTTGTGCATTTTT 60 TCATAAGATG AGTCATATGT TTTAAATTGT AGTAATGAAA AACAGTATTATATCATAATG 120 AATTGGTATC TTAATAAAAG AGATGGAGGT AACTTATGGA TAACAATCCGAACATCAATG 180 AATGCATTCC TTATAATTGT TTAAGTAACC CTGAAGTAGA AGTATTAGGTGGAGAAAGAA 240 TAGAAACTGG TTACACCCCA ATCGATATTT CCTTGTCGCT AACGCAATTTCTTTTGAGTG 300 AATTTGTTCC CGGTGCTGGA TTTGTGTTAG GACTAGTTGA TATAATATGGGGAATTTTTG 360 GTCCCTCTCA ATGGGACGCA TTTCCTGTAC AAATTGAACA GTTAATTAACCAAAGAATAG 420 AAGAATTCGC TAGGAACCAA GCCATTTCTA GATTAGAAGG ACTAAGCAATCTTTATCAAA 480 TTTACGCAGA ATCTTTTAGA GAGTGGGAAG CAGATCCTAC TAATCCAGCATTAAGAGAAG 540 AGATGCGTAT TCAATTCAAT GACATGAACA GTGCCCTTAC AACCGCTATTCCTCTTTTTG 600 CAGTTCAAAA TTATCAAGTT CCTCTTTTAT CAGTATATGT TCAAGCTGCAAATTTACATT 660 TATCAGTTTT GAGAGATGTT TCAGTGTTTG GACAAAGGTG GGGATTTGATGCCGCGACTA 720 TCAATAGTCG TTATAATGAT TTAACTAGGC TTATTGGCAA CTATACAGATCATGCTGTAC 780 GCTGGTACAA TACGGGATTA GAGCGTGTAT GGGGACCGGA TTCTAGAGATTGGATAAGAT 840 ATAATCAATT TAGAAGAGAA TTAACACTAA CTGTATTAGA TATCGTTTCTCTATTTCCGA 900 ACTATGATAG TAGAACGTAT CCAATTCGAA CAGTTTCCCA ATTAACAAGAGAAATTTATA 960 CAAACCCAGT ATTAGAAAAT TTTGATGGTA GTTTTCGAGG CTCGGCTCAGGGCATAGAAG 1020 GAAGTATTAG GAGTCCACAT TTGATGGATA TACTTAACAG TATAACCATCTATACGGATG 1080 CTCATAGAGG AGAATATTAT TGGTCAGGGC ATCAAATAAT GGCTTCTCCTGTAGGGTTTT 1140 CGGGGCCAGA ATTCACTTTT CCGCTATATG GAACTATGGG AAATGCAGCTCCACAACAAC 1200 GAATTGTTGC TCAACTAGGT CAGGGCGTGT ATAGAACATT ATCGTCCACTTTATGTAGAA 1260 GACCTTTTAA TATAGGGATA AATAATCAAC AACTATCTGT TCTTGACGGGACAGAATTTG 1320 CTTATGGAAC CTCCTCAAAT TTGCCATCCG CTGTATACAG AAAAAGCGGAACGGTAGATT 1380 CGCTGGATGA AATACCGCCA CAGAATAACA ACGTGCCACC TAGGCAAGGATTTAGTCATC 1440 GATTAAGCCA TGTTTCAATG TTTCGTTCAG GCTTTAGTAA TAGTAGTGTAAGTATAATAA 1500 GAGCTCCTAT GTTCTCTTGG ATACATCGTA GTGCTGAATT TAATAATATAATTCCTTCAT 1560 CACAAATTAC ACAAATACCT TTAACAAAAT CTACTAATCT TGGCTCTGGAACTTCTGTCG 1620 TTAAAGGACC AGGATTTACA GGAGGAGATA TTCTTCGAAG AACTTCACCTGGCCAGATTT 1680 CAACCTTAAG AGTAAATATT ACTGCACCAT TATCACAAAG ATATCGGGTAAGAATTCGCT 1740 ACGCTTCTAC CACAAATTTA CAATTCCATA CATCAATTGA CGGAAGACCTATTAATCAGG 1800 GGAATTTTTC AGCAACTATG AGTAGTGGGA GTAATTTACA GTCCGGAAGCTTTAGGACTG 1860 TAGGTTTTAC TACTCCGTTT AACTTTTCAA ATGGATCAAG TGTATTTACGTTAAGTGCTC 1920 ATGTCTTCAA TTCAGGCAAT GAAGTTTATA TAGATCGAAT TGAATTTGTTCCGGCAGAAG 1980 TAACCTTTGA GGCAGAATAT GATTTAGAAA GAGCACAAAA GGCGGTGAATGAGCTGTTTA 2040 CTTCTTCCAA TCAAATCGGG TTAAAAACAG ATGTGACGGA TTATCATATTGATCAAGTAT 2100 CCAATTTAGT TGAGTGTTTA TCTGATGAAT TTTGTCTGGA TGAAAAAAAAGAATTGTCCG 2160 AGAAAGTCAA ACATGCGAAG CGACTTAGTG ATGAGCGGAA TTTACTTCAAGATCCAAACT 2220 TTAGAGGGAT CAATAGAGAA CTAGACCGTG GCTGGAGAGG AAGTACGGATATTACCATCC 2280 AAGGAGGCGA TGACGTATTC AAAGAGAATT ACGTTACGCT ATTGGGTACCTTTGATGAGT 2340 GCTATCCAAC GTATTTATAT CAAAAAATAG ATGAGTCGAA ATTAAAAGCCTATACCCGTT 2400 ACCAATTAAG AGGGTATATC GAAGATAGTC AAGACTTAGA AATCTATTTAATTCGCTACA 2460 ATGCCAAACA CGAAACAGTA AATGTGCCAG GTACGGGTTC CTTATGGCCGCTTTCAGCCC 2520 CAAGTCCAAT CGGAAAATGT GCCCATCATT CCCATCATTT CTCCTTGGACATTGATGTTG 2580 GATGTACAGA CTTAAATGAG GACTTAGGTG TATGGGTGAT ATTCAAGATTAAGACGCAAG 2640 ATGGCCATGC AAGACTAGGA AATCTAGAAT TTCTCGAAGA GAAACCATTAGTAGGAGAAG 2700 CACTAGCTCG TGTGAAAAGA GCGGAGAAAA AATGGAGAGA CAAACGTGAAAAATTGGAAT 2760 GGGAAACAAA TATTGTTTAT AAAGAGGCAA AAGAATCTGT AGATGCTTTATTTGTAAACT 2820 CTCAATATGA TAGATTACAA GCGGATACCA ACATCGCGAT GATTCATGCGGCAGATAAAC 2880 GCGTTCATAG CATTCGAGAA GCTTATCTGC CTGAGCTGTC TGTGATTCCGGGTGTCAATG 2940 CGGCTATTTT TGAAGAATTA GAAGGGCGTA TTTTCACTGC ATTCTCCCTATATGATGCGA 3000 GAAATGTCAT TAAAAATGGT GATTTTAATA ATGGCTTATC CTGCTGGAACGTGAAAGGGC 3060 ATGTAGATGT AGAAGAACAA AACAACCACC GTTCGGTCCT TGTTGTTCCGGAATGGGAAG 3120 CAGAAGTGTC ACAAGAAGTT CGTGTCTGTC CGGGTCGTGG CTATATCCTTCGTGTCACAG 3180 CGTACAAGGA GGGATATGGA GAAGGTTGCG TAACCATTCA TGAGATCGAGAACAATACAG 3240 ACGAACTGAA GTTTAGCAAC TGTGTAGAAG AGGAAGTATA TCCAAACAACACGGTAACGT 3300 GTAATGATTA TACTGCGACT CAAGAAGAAT ATGAGGGTAC GTACACTTCTCGTAATCGAG 3360 GATATGACGG AGCCTATGAA AGCAATTCTT CTGTACCAGC TGATTATGCATCAGCCTATG 3420 AAGAAAAAGC ATATACAGAT GGACGAAGAG ACAATCCTTG TGAATCTAACAGAGGATATG 3480 GGGATTACAC ACCACTACCA GCTGGCTATG TGACAAAAGA ATTAGAGTACTTCCCAGAAA 3540 CCGATAAGGT ATGGATTGAG ATCGGAGAAA CGGAAGGAAC ATTCAACGTGGACAGCGTGG 3600 AATTACTTCT TATGGAGGAA TAATATATGC TTTATAATGT AAGGTGTGCAAATAAAGAAT 3660 GATTACTGAC TTGTATTGAC AGATAAATAA GGAAATTTTT ATATGAATAAAAAACGGGCA 3720 TCACTCTTAA AAGAATGATG TCCGTTTTTT GTATGATTTA ACGAGTGATATTTAAATGTT 3780 TTTTTTGCGA AGGCTTTACT TAACGGGGTA CCGCCACATG CCCATCAACTTAAGAATTTG 3840 CACTACCCCC AAGTGTCAAA AAACGTTATT CTTTCTAAAA AGCTAGCTAGAAAGGATGAC 3900 ATTTTTTATG AATCTTTCAA TTCAAGATGA ATTACAACTA TTTTCTGAAGAGCTGTATCG 3960 TCATTTAACC CCTTCTCTTT TGGAAGAACT CGCTAAAGAA TTAGGTTTTGTAAAAAGAAA 4020 ACGAAAGTTT TCAGGAAATG AATTAGCTAC CATATGTATC TGGGGCAGTCAACGTACAGC 4080 GAGTGATTCT CTCGTTCGAC TATGCAGTCA ATTACACGCC GCCACAGCACTCTTATGAGT 4140 CCAGAAGGAC TCAATAAACG CTTTGATAAA AAAGCGGTTG AATTTTTGAAATATATTTTT 4200 TCTGCATTAT GGAAAAGTAA ACTTTGTAAA ACATCAGCCA TTTCAAGTGCAGCACTCACG 4260 TATTTTCAAC GAATCCGTAT TTTAGATGCG ACGATTTTCC AAGTACCGAAACATTTAGCA 4320 CATGTATATC CTGGGTCAGG TGGTTGTGCA CAAACTGCAG 4360

What is claimed is:
 1. A method for producing a transformed cotton plantcomprising the steps of: providing a cotton explant selected from thegroup consisting of hypocotyl, cotyledon, immature zygotic embryos andmixtures thereof; incubating the cotton explant in the presence of avector comprising DNA encoding a selectable marker to produce a treatedexplant; growing the treated explant in a sucrose-free, first callusgrowth medium supplemented with glucose as the primary carbon sourceuntil the secretion of phenolic compounds cease and cotton callus isformed; and selecting transformed embryogenic cotton callus.
 2. Themethod as recited in claim 1, wherein the vector is derived from anAgrobacterium plasmid.
 3. The method as recited in claim 1, furthercomprising the step of incubating the treated explant in a callus growthmedium toxic to Agrobacterium but non-toxic to the explant or callus. 4.The method as recited in claim 1, wherein the treated explant is grownunder illumination cycles of 16 hours of light and 8 hours of dark. 5.The method as recited in claim 4, wherein the treated explant is grownin a light intensity of 2,000 to 4,000 lux during the hours of light ofthe illumination cycles.
 6. The method as recited in claim 4, whereinthe treated explant is grown in a light intensity of 3,000 to 4,000 luxduring the hours of light of the illumination cycles.
 7. The method asrecited in claim 1, wherein the treated explant is grown at atemperature of 25° C. to 35° C.
 8. The method as recited in claim 1,wherein the treated explant is grown at a temperature of 30° C.
 9. Themethod as recited in claim 1, wherein the treated explant is grown forabout 3 to 4 weeks to produce callus.
 10. The method as recited in claim1, wherein the first callus growth medium is further supplemented withthiamine, kinetin, inositol and naphthaleneactic acid.
 11. The method asrecited in claim 1, further comprising the step, after the secretion ofphenolic compounds cease, transferring the callus to a second callusgrowth medium for the formation of embryogenic callus.
 12. The method asrecited in claim 11, wherein sucrose is the primary carbon source in thesecond callus growth medium.
 13. The method as recited in claim 12,wherein the second callus growth medium is supplemented with thiamine,kinetin, inositol and naphthaleneacetic acid.
 14. The method as recitedin claim 1, further comprising the steps of: obtaining a transformedcotton embryo from the transformed embryogenic cotton callus,transferring the transformed cotton embryo to an embryo germinationmedium, and culturing the transformed cotton embryo germination mediumuntil a cotton plantlet is formed from the transformed embryo.
 15. Themethod as recited in claim 14, wherein the embryo germination medium issupplemented with casein hydrolysate and a source of ammonia.
 16. Themethod as recited in claim 14, wherein the transformed embryo iscultured under illumination cycles of 16 hours of light and 8 hours ofdark.
 17. The method as recited in claim 16, wherein the transformedembryo is cultured in a light intensity of 2,000 to 4,000 lux during thehours of light of the illumination cycles.
 18. The method as recited inclaim 16, wherein the transformed embryo is cultured in a lightintensity of 3,000 to 4,000 lux during the hours of light of theillumination cycles.
 19. The method as recited in claim 14, wherein thetransformed embryo is cultured at a temperature of 25° C. to 35° C. 20.The method as recited in claim 14, wherein the transformed embryo iscultured at a temperature of 30° C.
 21. The method as recited in claim14, further comprising the step of culturing the transformed cottonembryo for about 2 to 3 weeks to produce cotton plantlets.
 22. Themethod as recited in claim 14, further comprising the steps oftransferring the plantlet to soil and growing the cotton plantlet untilthe plantlet is sufficiently matured to withstand transfer to agreenhouse or field for growth to final maturity.
 23. The method asrecited in claim 1, further comprising the steps of: sterilization acotton seed; transferring the seed to a seed germination medium; growingthe seed in the seed germination medium until a seedling is produced;and preparing explants from the seedling.
 24. The method as recited inclaim 3, wherein the callus growth medium toxic to Agrobacteriumcomprises cefotaxime.
 25. The method as recited in claim 1, wherein thefirst callus growth medium is a Murashinge and Skoog medium supplementedwith naphthaleneacetic acid in an amount of 1 to 10 mg/l.
 26. The methodas recited in claim 1, wherein the selectable marker confers resistanceto a compound toxic to non-transformed callus.
 27. The method as recitedin claim 1, wherein the selectable marker is neomycinphosphotransferase.
 28. The method as recited in claim 1, wherein thevector further comprises heterologous DNA, in addition to the DNAencoding the selectable marker, wherein the heterologous DNA encodes aprotein that, wherein expressed, confers a desired trait to transformedembryogenic cotton callus or cotton plants derived from transformedembryogenic callus.
 29. The method as recited in claim 28, wherein theheterologous DNA encodes a protein that confers antibiotic resistance.30. The method as recited in claim 29, wherein the antibiotic resistanceis kanamycin resistance or G418 resistance.
 31. The method as recited inclaim 28, wherein the heterologous DNA encodes neomycinphosphotransferase.
 32. The method as recited in claim 28, wherein theheterologous DNA encodes a protein that confers herbicide resistance.33. The method as recited in claim 32, wherein the herbicide resistanceis glyphosate resistance.
 34. The method as recited in claim 28, whereinthe heterologous DNA comprises a mutant aroA gene.
 35. The method asrecited in claim 28, wherein the heterologous DNA encodes an alteredform of 5-enolpyruvyl shikimate 3-phosphate synthase.
 36. The method asrecited in claim 1, wherein the transformed callus is selected bygrowing the transformed callus in a medium supplemented with a compoundtoxic to non-transformed callus but non-toxic to the transformed callus.37. The method as recited in claim 36, wherein the transformed callus isselected by growing the callus in a medium supplemented with kanamycinor G418.
 38. A method for transforming a cotton plant comprising thesteps of: providing a cotton explant selected from the group consistingof hypocotyl, cotyledon, immature zygotic embryos and mixtures thereof;culturing the explant in a sucrose-free first callus growth mediumsupplemented with thiamine, kinetin, inositol, naphthaleneacetic acidand glucose until secretion of phenolic compounds cease andundifferentiated cotton callus is formed from the explant; culturing theundifferentiated callus in a glucose-free second callus growth mediumsupplemented with inositol, naphthaleneacetic acid and sucrose untilembryogenic cotton callus is formed from the undifferentiated callus;incubating the embryogenic cotton callus in the presence of a plasmidvector derived from an Agrobacterium plasmid comprising DNA encoding aselectable marker to produce treated cotton callus; incubating thetreated cotton callus in a callus growth medium toxic to Agrobacteriumbut non-toxic to callus; and selecting transformed embryogenic cottoncallus.
 39. The method as recited in claim 38, further comprising thesteps of: suspending the embryogenic cotton callus in a suspensionmedium formed of the glucose-free second callus growth medium to form asuspension culture; and growing the embryogenic cotton callus in thesuspension culture.
 40. The method as recited in claim 38, furthercomprising the steps of: obtaining a transformed cotton embryo from thetransformed embryogenic cotton callus; transferring the transformedcotton embryo to an embryo germination medium; and culturing thetransformed cotton embryo germination medium until a transformed cottonplantlet is formed from the transformed embryo.
 41. The method asrecited in any one of claims 1-28, 29-30, 31, and 32-40, wherein theexplant is derived from a cotton seedling selected from the groupconsisting of Acala SJ2, Acala SJ4, Acala SJ-C1, Acala B1654-26, AcalaB1654-43, Acala B3991, Acala GC510, Acala GAM1, Acala C1, Acala Royale,Acala Maxxa, Acala Prema, Acala B638, Acala B1810, Acala B2724, AcalaB4894, Acala B5002, STONEVILLE 825, DP61, DP77, DES119, McN235, HBX87,HBX191, HBX107, CHEMBRED A1, CHEMBRED A2, CHEMBRED A3, CHEMBRED A4,CHEMBRED B1, CHEMBRED B2, CHEMBRED B3, CHEMBRED C1, CHEMBRED C2,CHEMBRED C3, CHEMBRED C4, PAYMASTER 145, HS26, HS46, SCIALA, PIMA S6 andORO BLANCO PIMA.
 42. The method as recited in claim 41, wherein theexplant is derived from a cotton seedling selected form the groupconsisting of Acala SJ2, Acala SJ4, Acala SJ-C1, Acala B1654-26, AcalaB1654-43, Acala B3991, Acala GC510, Acala GAM1, Acala C1, Acala Royale,Acala Maxxa, Acala Prema, Acala B638, Acala B1810, Acala B2724, AcalaB4894, Acala B5002.
 43. The method as recited in claim 41 wherein theexplant is derived from a cotton seedling selected from the groupconsisting of STONEVILLE 825, DP61, DP77, DES119, McN235, HBX87, HBX191,HBX107, CHEMBRED A1, CHEMBRED A2, CHEMBRED A3, CHEMBRED A4, CHEMBRED B1,CHEMBRED B2, CHEMBRED B3, CHEMBRED C1, CHEMBRED C2, CHEMBRED C3,CHEMBRED C4, PAYMASTER 145, HS26, HS46, SICALA, PIMA S6 and ORO BLANCOPIMA.
 44. The method as recited in claim 41, wherein the explant isderived from a cotton seedling selected from the group consisting ofAcala SJ2, Acala SJ-C1, Acala 1654-26, Acala B131654-43, Acala GC510,Acala B1810, and Acala B2724.
 45. The method as recited in claim 41,wherein the explant is derived from CHEMBRED B2.
 46. The method asrecited in claim 41, wherein the explant is derived from a cottonseedling selected from the group consisting of Acala SJ-C1, AcalaB1654-26, Acala B1654-43, Acala B1810, Acala B2724, and CHEMBRED B 2.47. A method for producing a transformed cotton plant comprising thesteps of: providing a culture of embryogenic cotton callus in or on amedium; incubating the culture of embryogenic cotton callus with anAgrobacterium derived plasmid vector comprising DNA encoding aselectable marker to produce treated callus; and selecting transformedembryogenic callus.
 48. The method as recited in claim 47, furthercomprising the step of incubating the treated callus in a callus, growthmedium toxic to Agrobacterium but non-toxic to treated callus.
 49. Themethod as recited in claim 47, wherein said culture is a suspensionculture.
 50. The method as recited in claim 49, wherein the amount ofthe embryogenic callus in the suspension culture is about 95 to about125 mg/ml of medium.
 51. The method as recited in claim 47, wherein thetreated callus is grown under illumination cycles of 16 hours of lightand 8 hours of dark.
 52. The method as recited in claim 51, wherein thetreated callus is grown in a light intensity of 2,000 to 4,000 luxduring the hours of light of the illumination cycles.
 53. The method asrecited in claim 51, wherein the treated callus is grown in a lightintensity of 3,000 to 4, 000 lux during the hours of light of theillumination cycles.
 54. The method as recited in claim 47, wherein thetreated callus is grown at a temperature of 25° C. to 35° C.
 55. Themethod as recited in claim 47, wherein the treated callus is grown at atemperature of 30° C.
 56. The method as recited in claim 47, wherein thetreated callus is grown for about 3 to 4 weeks to produce transformedembryogenic callus.
 57. The method as recited in claim 47, furthercomprising the steps of: obtaining a transformed cotton embryo from thetransformed embryogenic cotton callus; transferring the transformedembryo to an embryo germination medium; and culturing the transformedcotton embryo on the embryo germination medium until a transformedcotton plantlet is formed from the transformed embryo.
 58. The method asrecited in claim 57, wherein the embryo germination medium is a Beasleyand Ting's medium containing about 500 mg/l casein hydrolysate and about1200 mg/l ammonium nitrate.
 59. The method as recited in claim 57,wherein the transformed embryo is cultured under illumination cycles of16 hours of light and 8 hours of dark.
 60. The method as recited inclaim 59, wherein the transformed embryo is cultured in a lightintensity of 2,000 to 4,000 lux during the hours of light of theillumination cycles.
 61. The method as recited in claim 59, wherein thetransformed embryo is cultured in a light intensity of 3,000 to 4,000lux during the hours of light of the illumination cycles.
 62. The methodas recited in claim 57, wherein the transformed embryo is cultured at atemperature of 25° C. to 35° C.
 63. The method as recited in claim 57,wherein the transformed embryo is cultured at a temperature of 30° C.64. The method as recited in claim 57, wherein the transformed embryo iscultured for about 2 to 3 weeks to produce plantlets.
 65. The method asrecited in claim 57, wherein the embryo germination medium issupplemented with casein hydrolysate and a source of ammonia.
 66. Themethod as recited in claim 47, comprising the steps of: sterilizing acotton seed; transferring the cotton seed to a seed germination medium;growing the cotton seed in the seed germination medium until a seedlingis produced; preparing explants from the seedling; culturing the explantin a sucrose-free first callus growth medium supplemented with glucoseas a primary carbon source until secretion of phenolic compounds ceaseand undifferentiated cotton callus is formed from the explant;transferring to and culturing the undifferentiated cotton callus in aglucose-free second callus growth medium supplemented with inositol,naphthaleneacetic acid and sucrose until embryogenic cotton callus isformed from the undifferentiated callus; and suspending the embryogeniccotton callus in a liquid suspension medium formed of the glucose freesecond callus growth medium to form a suspension culture of embryogeniccotton callus; and growing the suspension culture of embryogenic cottoncallus.
 67. The method as recited in claim 66, wherein the first callusgrowth medium is further supplemented with thiamine, kinetin, inositol,and naphthaleneacetic acid.
 68. The method as recited in claim 66,wherein the first callus growth medium is a Murashige and Skoog mediumand naphthaleneacetic acid is in an amount of about 1 to about 10 mg/l.69. The method as recited in claim 57, further comprising the steps oftransferring the transformed cotton plantlet to soil and growing thetransformed plantlet until the transformed plantlet is sufficientlymatured to withstand transfer to a greenhouse or field for growth tofinal maturity.
 70. The method as recited in claim 48, wherein thecallus growth medium toxic to Agrobacterium comprises cefotaxime. 71.The method as recited in claim 47, wherein the selectable marker isneomycin phosphotransferase.
 72. The method as recited in claim 47,wherein the vector further comprises heterologous DNA, in addition tothe DNA encoding the selectable marker, wherein the heterologous DNAencodes a protein that, when expressed, confers a desired trait to thetransformed embryogenic cotton callus or to cotton plants derived fromthe transformed embryogenic callus.
 73. The method as recited in claim72, wherein the heterologous DNA encodes a protein that confersantibiotic resistance.
 74. The method as recited in claim 73, whereinthe antibiotic resistance is kanamycin resistance or G418 resistance.75. The method as recited in claim 72, wherein the heterologous DNAencodes neomycin phosphotransferase.
 76. The method as recited in claim72, wherein the heterologous DNA encodes a protein that confersherbicide resistance.
 77. The method as recited in claim 76, wherein theherbicide resistance is glyphosate resistance.
 78. The method as recitedin claim 72, wherein the heterologous DNA comprises a mutant aroA gene.79. The method as recited in claim 72, wherein the heterologous DNAencodes an altered form of 5-enolpyruvyl shikimate 3-phosphate synthase.80. The method as recited in claim 47, wherein the transformed callus isselected by growing the transformed callus in a medium supplemented witha compound toxic to non-transformed callus but non-toxic to thetransformed callus.
 81. The method as recited in claim 47, wherein thetransformed embryogenic callus is selected by growing the transformedembryogenic callus in medium supplemented with kanamycin or G418. 82.The method as recited in any one of claims 47, 48-72, 73-75, 76-81, and49, wherein the embryogenic callus is derived from a cotton plantvariety selected from the group consisting of Acala SJ2, Acala SJ4,Acala SJ-C1, Acala B1654-26, Acala B1654-43, Acala B3991, Acala GC510,Acala GAM1, Acala C1, Acala Royale, Acala Maxxa, Acala Prema, AcalaB638, Acala B1810, Acala B2724, Acala B4894, Acala B5002, STONEVILLE825, DP61, DP77, DES119, McN235, HBX87, HBX191, HBX107, CHEMBRED A1,CHEMBRED A2CHEMBRED A3, CHEMBRED A4, CHEMBRED B1, CHEMBRED B2, CHEMBREDB3, CHEMBRED C1, CHEMBRED C2, CHEMBRED C3, CHEMBRED C4, PAYMASTER 145,HS26, HS46, SICALA, PIMA S6 and ORO BLANCO PIMA.
 83. The method asrecited in claim 82, wherein the embryogenic callus is derived from acotton plant variety selected from the group consisting of Acala SJ2,Acala SJ4, Acala SJ-C1, Acala 1654-26, Acala B1654-43, Acala B3991,Acala GC510, Acala GAM1, Acala C1, Acala Royale, Acala Maxxa, AcalaPrema, Acala B638, Acala B1810, Acala B2724, Acala B4894, and AcalaB5002.
 84. The method as recited in claim 82, wherein the embryogeniccallus is derived from a cotton plant variety selected from the groupconsisting of STONEVILLE 825, DP61, DP77, DES119, McN235, HBX87, HBX191,HBX107, CHEMBRED A1, CHEMBRED A2CHEMBRED A3, CHEMBRED A4, CHEMBRED B1,CHEMBRED B2, CHEMBRED B3, CHEMBRED C1, CHEMBRED C2, CHEMBRED C3,CHEMBRED C4, PAYMASTER 145, HS26, HS46, SICALA, PIMA S6 and ORO BLANCOPIMA.
 85. The method as recited in claim 83, wherein the embryogeniccallus is derived from a cotton plant variety selected from the groupconsisting of Acala SJ2, Acala SJ-C1, Acala 1654-26, Acala B1654-43,Acala GC510, Acala B1810, and Acala B2724.
 86. The method as recited inclaim 84, wherein the embryogenic callus is derived from CHEMBRED B2.87. The method as recited in claim 82, wherein the embryogenic callus isderived from a cotton plant variety selected from the group consistingof Acala SJ-C1, Acala B1654-26, Acala B1654-43, Acala B1810, AcalaB2724, and CHEMBRED B2.
 88. The method as recited in claim 15, whereinsaid germination medium comprises a Beasley and Ting's medium containingabout 500 mg/l casein hydrolysate and about 1200 mg/l ammonium nitrate.89. The method as recited in claim 40, wherein said germination mediumcomprises a Beasley and Ting's medium containing about 500 mg/l caseinhydrolysate and about 1200 mg/l ammonium nitrate.